Update deps

[patrys]

This updates most of the outdated dependencies.

I was unable to bump our Django version to 2.1 because of graphql-python/graphene-django#492

Closes #2507

Pull Request Checklist

1. Privileged views and APIs are guarded by proper permission checks.
2. All visible strings are translated with proper context.
3. All data-formatting is locale-aware (dates, numbers, and so on).
4. Database queries are optimized and the number of queries is constant.
5. The changes are tested.
6. The code is documented (docstrings, project documentation).

[NyanKiyoshi]

Note: this closes #2507.

[codecov]

Codecov Report

Merging #2601 into master will decrease coverage by 0.03%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2601      +/-   ##
==========================================
- Coverage   89.61%   89.58%   -0.04%     
==========================================
  Files         204      204              
  Lines        9893     9893              
  Branches      931      931              
==========================================
- Hits         8866     8863       -3     
- Misses        743      746       +3     
  Partials      284      284

Impacted Files	Coverage Δ
saleor/account/i18n.py	94.02% <0%> (-2.24%)	⬇️

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[NyanKiyoshi]

This also fixes #1809 as google-i18n-address 2.3.1 adds Cuba (CU) and other missing countries. (c.f. mirumee/google-i18n-address#36)

Now, do we still want to implement the change suggested by @maarcingebala?

A much better idea would be to have a default address form which will be the fallback in cases when localized address form can't be provided.

I feel like it may not be needed as it is very unlikely that the user will have an unknown country code saved into the database. But I may be wrong.