feat: Schema validation for SimpleTable

[mgrandis]

Issue #, if available: N/A

Description of changes:
Added schema validation for the AWS::Serverless::SimpleTable resource.

Description of how you validated changes:
Unit tests with yaml files + ran the validation over the Translator test files.

One file returned a validation error and was updated:
tests/translator/input/simple_table_with_extra_tags.yaml

Indeed, according to the CFN doc, a tag value must be at least 1 character long, this test file had a tag value with an empty string.

Checklist:

• Add/update tests using:
  • Correct values
  • Bad/wrong values (None, empty, wrong type, length, etc.)
  • Intrinsic Functions
• make pr passes
• Update documentation
• Verify transformed template deploys and application functions as expected

Examples?

Please reach out in the comments, if you want to add an example. Examples will be
added to sam init through https://github.com/awslabs/aws-sam-cli-app-templates/

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

[codecov-commenter]

Codecov Report

Merging #2195 (1415d91) into develop (e7a1496) will increase coverage by 0.80%.
The diff coverage is 98.27%.

@@             Coverage Diff             @@
##           develop    #2195      +/-   ##
===========================================
+ Coverage    93.58%   94.39%   +0.80%     
===========================================
  Files           90       95       +5     
  Lines         6124     6542     +418     
  Branches      1260     1319      +59     
===========================================
+ Hits          5731     6175     +444     
+ Misses         183      170      -13     
+ Partials       210      197      -13     

Impacted Files	Coverage Δ
samtranslator/model/lambda_.py	93.10% <ø> (ø)
samtranslator/plugins/globals/globals.py	99.05% <ø> (ø)
samtranslator/translator/logical_id_generator.py	100.00% <ø> (+9.09%)	⬆️
samtranslator/region_configuration.py	77.77% <63.63%> (-22.23%)	⬇️
samtranslator/translator/translator.py	97.26% <90.00%> (+0.07%)	⬆️
samtranslator/swagger/swagger.py	94.00% <92.50%> (+0.63%)	⬆️
samtranslator/__init__.py	100.00% <100.00%> (ø)
samtranslator/feature_toggle/dialup.py	100.00% <100.00%> (ø)
samtranslator/feature_toggle/feature_toggle.py	100.00% <100.00%> (+12.16%)	⬆️
samtranslator/metrics/method_decorator.py	100.00% <100.00%> (ø)
... and 30 more

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