Add support for AWS CodeBuild as CI provider

[rasarora]

Add support for AWS CodeBuild as CI provider

[codecov]

Codecov Report

Merging #56 into master will increase coverage by 0.20%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master      #56      +/-   ##
==========================================
+ Coverage   91.93%   92.13%   +0.20%     
==========================================
  Files           1        1              
  Lines         347      356       +9     
==========================================
+ Hits          319      328       +9     
  Misses         28       28              

Impacted Files	Coverage Δ
lib/codecov.rb	92.13% <100.00%> (+0.20%)	⬆️

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[thomasrockhu]

@rasarora thanks for this!

[klausbadelt]

@thomasrockhu excited to see official CodeBuild support.

CODEBUILD_ID is nowhere mentioned in the CodeBuild docs though - you guys sure that's set by AWS? (I used CODEBUILD_BUILD_ID to identify CodeBuild in my previous PR).

Sorry for the late question!

[thomasrockhu]

@klausbadelt, a little confused here, I think the PR is using CODEBUILD_BUILD_ID