Update with changes from other plugins

[eduardomourar]

Issue #, if available:

Description of changes:

Update with changes so it is in sync with other Cloudformation CLI plugins.

[codecov]

Codecov Report

Merging #14 into master will increase coverage by 0.02%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master      #14      +/-   ##
==========================================
+ Coverage   94.83%   94.86%   +0.02%     
==========================================
  Files          13       13              
  Lines         871      876       +5     
  Branches      136      137       +1     
==========================================
+ Hits          826      831       +5     
  Misses         45       45              

Flag	Coverage Δ
#unittests	94.86% <100.00%> (+0.02%)	⬆️

Impacted Files	Coverage Δ
src/callback.ts	100.00% <ø> (ø)
python/rpdk/typescript/codegen.py	100.00% <100.00%> (ø)
python/rpdk/typescript/resolver.py	100.00% <100.00%> (ø)
src/interface.ts	96.22% <100.00%> (ø)
src/proxy.ts	82.53% <100.00%> (ø)
src/resource.ts	95.04% <100.00%> (ø)
src/utils.ts	83.05% <100.00%> (ø)

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