Upgrade to Python 3.9

[patrys]

Use Python 3.9 and upgrade to the latest Sentry SDK. Python 3.9 introduces a number of optimizations that we can take advantage of.

Impact

• New migrations
• New/Updated API fields or mutations
• Deprecated API fields or mutations
• Removed API types, fields, or mutations
• Documentation needs to be updated

Pull Request Checklist

• Privileged queries and mutations are guarded by proper permission checks
• Database queries are optimized and the number of queries is constant
• Database migration files are up to date
• The changes are tested
• GraphQL schema and type definitions are up to date
• Changes are mentioned in the changelog

[maarcingebala]

Please fix the conflicts. Is this supposed to be released in 2.11?

[patrys]

Will fix, it's an old branch and I think it should target 3.0.

[codecov]

Codecov Report

Merging #6390 (ced5d66) into master (45b9ac9) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #6390   +/-   ##
=======================================
  Coverage   92.65%   92.65%           
=======================================
  Files         392      392           
  Lines       26423    26423           
  Branches     2730     2730           
=======================================
  Hits        24482    24482           
  Misses       1363     1363           
  Partials      578      578           

---

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[db-queries]

Here is the report for ced5d66 (mirumee:upgrade-python)
Base comparison is 45b9ac9.

No differences were found.

# saleor.graphql.accountbenchmark account
  test name                                                  	left count 	right count	duplicate count
  -----------------------------------------------------------	-----------	-----------	---------------
  delete staff members                                       	         32	         32	              0
  query staff user                                           	         20	         20	              4
  staff create                                               	         22	         22	              4
  staff update groups and permissions                        	         33	         33	              5

# saleor.graphql.accountbenchmark permission group
  test name                                                  	left count 	right count	duplicate count
  -----------------------------------------------------------	-----------	-----------	---------------
  permission group create                                    	         19	         19	              2
  permission group delete                                    	         20	         20	              3
  permission group query                                     	          7	          7	              0
  permission group update                                    	         33	         33	              1
  permission group update remove users with manage staff     	         27	         27	              3

# saleor.graphql.attributebenchmark attribute
  test name                                                  	left count 	right count	duplicate count
  -----------------------------------------------------------	-----------	-----------	---------------
  query attribute                                            	          7	          7	              2
  query attributes                                           	         11	         11	              3

# saleor.graphql.checkoutbenchmark checkout mutations
  test name                                                  	left count 	right count	duplicate count
  -----------------------------------------------------------	-----------	-----------	---------------
  add billing address to checkout                            	        120	        120	             72
  add shipping to checkout                                   	        109	        109	             59
  checkout email update                                      	         82	         82	             49
  checkout payment charge                                    	         67	         67	             31
  checkout shipping address update                           	        101	        101	             47
  checkout voucher code                                      	        151	        151	            100
  complete checkout                                          	        167	        167	             64
  create checkout                                            	        192	        192	            104
  update checkout lines                                      	        186	        186	            105

# saleor.graphql.checkoutbenchmark homepage
  test name                                                  	left count 	right count	duplicate count
  -----------------------------------------------------------	-----------	-----------	---------------
  user checkout details                                      	         75	         75	             36

# saleor.graphql.discountbenchmark sales
  test name                                                  	left count 	right count	duplicate count
  -----------------------------------------------------------	-----------	-----------	---------------
  sales query with channel slug                              	         16	         16	              0
  sales query withot channel slug                            	         15	         15	              0

# saleor.graphql.discountbenchmark vouchers
  test name                                                  	left count 	right count	duplicate count
  -----------------------------------------------------------	-----------	-----------	---------------
  vouchers query with channel slug                           	         16	         16	              0
  vouchers query withot channel slug                         	         15	         15	              0

# saleor.graphql.menubenchmark homepage
  test name                                                  	left count 	right count	duplicate count
  -----------------------------------------------------------	-----------	-----------	---------------
  retrieve main menu                                         	          5	          5	              0
  retrieve secondary menu                                    	          5	          5	              0

# saleor.graphql.orderbenchmark order
  test name                                                  	left count 	right count	duplicate count
  -----------------------------------------------------------	-----------	-----------	---------------
  user order details                                         	         22	         22	              2

# saleor.graphql.pagebenchmark page type
  test name                                                  	left count 	right count	duplicate count
  -----------------------------------------------------------	-----------	-----------	---------------
  query page type                                            	         17	         17	              5
  query page types                                           	         19	         19	              5

# saleor.graphql.productbenchmark category
  test name                                                  	left count 	right count	duplicate count
  -----------------------------------------------------------	-----------	-----------	---------------
  category view                                              	         22	         22	              1

# saleor.graphql.productbenchmark collection
  test name                                                  	left count 	right count	duplicate count
  -----------------------------------------------------------	-----------	-----------	---------------
  collection view                                            	          5	          5	              0
  retrieve collection channel listings                       	          5	          5	              0

# saleor.graphql.productbenchmark homepage
  test name                                                  	left count 	right count	duplicate count
  -----------------------------------------------------------	-----------	-----------	---------------
  report product sales                                       	         10	         10	              3
  retrieve product list                                      	          4	          4	              0

# saleor.graphql.productbenchmark product
  test name                                                  	left count 	right count	duplicate count
  -----------------------------------------------------------	-----------	-----------	---------------
  product details                                            	         25	         25	              0
  retrieve channel listings                                  	         16	         16	              0
  retrieve product attributes                                	          7	          7	              0
  retrive products with product types and attributes         	          5	          5	              0

# saleor.graphql.productbenchmark variant
  test name                                                  	left count 	right count	duplicate count
  -----------------------------------------------------------	-----------	-----------	---------------
  product variant bulk create                                	         53	         53	              2
  retrieve variant list                                      	         22	         22	              2

# saleor.graphql.productbenchmark variant stocks
  test name                                                  	left count 	right count	duplicate count
  -----------------------------------------------------------	-----------	-----------	---------------
  product variants stocks create                             	         22	         22	              5
  product variants stocks delete                             	         19	         19	              5
  product variants stocks update                             	         27	         27	              5

# saleor.graphql.producttest product sorting attributes
  test name                                                  	left count 	right count	duplicate count
  -----------------------------------------------------------	-----------	-----------	---------------
  sort product not having attribute data                     	         20	         20	              0

# saleor.graphql.shippingbenchmark shipping methods
  test name                                                  	left count 	right count	duplicate count
  -----------------------------------------------------------	-----------	-----------	---------------
  vouchers query with channel slug                           	         10	         10	              0
  vouchers query without channel slug                        	          9	          9	              0

# saleor.graphql.shopbenchmark homepage
  test name                                                  	left count 	right count	duplicate count
  -----------------------------------------------------------	-----------	-----------	---------------
  retrieve shop                                              	          2	          2	              0