feat: CodeCommit events support (#964)

[eduardovra]

Issue: #964

Description of changes:
Add new source event type CodeCommit.
This creates an EventBridge Rule to trigger a lambda function after any changes in a repository.

Description of how you validated changes:
Created a CodeCommit repository from the AWS console, and then deployed a template with a lambda function the was successfully triggered.

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.

[alexw91]

Codecov Report

Merging #1443 into develop will decrease coverage by 0.09%.
The diff coverage is n/a.

@@             Coverage Diff             @@
##           develop    #1443      +/-   ##
===========================================
- Coverage    94.42%   94.32%   -0.10%     
===========================================
  Files           78       78              
  Lines         4554     4704     +150     
  Branches       912      936      +24     
===========================================
+ Hits          4300     4437     +137     
- Misses         119      123       +4     
- Partials       135      144       +9     

Impacted Files	Coverage Δ
samtranslator/model/apigateway.py	97.10% <0.00%> (-0.86%)	⬇️
samtranslator/swagger/swagger.py	92.43% <0.00%> (-0.46%)	⬇️
samtranslator/model/api/api_generator.py	95.04% <0.00%> (-0.10%)	⬇️
...nslator/model/preferences/deployment_preference.py	100.00% <0.00%> (ø)	⬆️
samtranslator/translator/translator.py	98.38% <0.00%> (+0.01%)	⬆️
samtranslator/model/sam_resources.py	94.06% <0.00%> (+0.07%)	⬆️
samtranslator/model/eventsources/push.py	90.43% <0.00%> (-0.10%)	⬇️
samtranslator/translator/logical_id_generator.py	90.90% <0.00%> (+0.90%)	⬆️

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