codepipeline: pollForSourceChanges defaults to true

[clareliguori]

All of the CodePipeline source actions currently default to enabling pollForSourceChanges, which is no longer the recommended configuration. These source actions should configure the recommended change-detection methods in the stack by default.

CodeCommit:
https://github.com/awslabs/aws-cdk/blob/master/packages/%40aws-cdk/aws-codecommit/lib/pipeline-action.ts#L57

S3:
https://github.com/awslabs/aws-cdk/blob/master/packages/%40aws-cdk/aws-s3/lib/pipeline-action.ts#L56

GitHub:
https://github.com/awslabs/aws-cdk/blob/master/packages/%40aws-cdk/aws-codepipeline/lib/github-source-action.ts#L69

[eladb]

I believe @skinny85 is working on this right now
#1026

[skinny85]

Thanks for reporting Claire. Yes, #1026 fixes it for CodeCommit, S3 and GitHub will soon follow suit.

[jesterhazy]

S3 Source action is still defaulting to true, and including pollForSourceChanges: false has no effect. This seems like a bug on top of a feature request.

[skinny85]

Thanks for reporting @jesterhazy. We're working on this right now in #1260.

[skinny85]

All of the CodePipeline Sources have been updated. Feel free to let us know if something doesn't work.

Thanks,
Adam