Function role tag propagation

[to-mc]

Issue #, if available: #1160

Description of changes: Enable propagation of tags from Serverless::Function resources to the IAM Roles generated. This includes the default tag (lambda:createdBy: SAM). Updated the expected output json files so the unit tests pass with tags now being automatically added to iam roles.

Description of how you validated changes: Followed "verifying transforms" guidance in the development guide with some basic templates. Ran unit tests with updated expected output json files.

Checklist:

• Write/update tests
• make pr passes
• Update documentation
• Verify transformed template deploys and application functions as expected
• Add/update example to examples/2016-10-31

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov-io]

Codecov Report

Merging #1194 into develop will increase coverage by <.01%.
The diff coverage is 100%.

@@             Coverage Diff             @@
##           develop    #1194      +/-   ##
===========================================
+ Coverage    94.33%   94.33%   +<.01%     
===========================================
  Files           72       72              
  Lines         3725     3726       +1     
  Branches       733      733              
===========================================
+ Hits          3514     3515       +1     
  Misses         107      107              
  Partials       104      104

Impacted Files	Coverage Δ
samtranslator/model/iam.py	81.25% <100%> (ø)	⬆️
samtranslator/model/sam_resources.py	95.61% <100%> (+0.01%)	⬆️

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[ShreyaGangishetty]

@cakepietoast thanks for contributing this feature!
Could you please add a unit test case by adding some tags on the AWS::Serverless::Function resource?
Otherwise this PR looks good to me

[to-mc]

@cakepietoast thanks for contributing this feature!
Could you please add a unit test case by adding some tags on the AWS::Serverless::Function resource?
Otherwise this PR looks good to me

There's already a test case in TestTranslatorEndToEnd basic_functions_with_tags that tests this functionality. Is there something more specific you'd like me to add?

[ShreyaGangishetty]

@cakepietoast That should be enough. I was looking for a SAM transform template output where user-defined tags get added to AWS::Iam::Role along with tags generated by SAM. Found it here.
Approving the changes. This looks good to me.

[keetonian]

This is great! Thank you for making this change!