feat(cdk): add the CodeDeployLambdaAlias Update Policy

[skinny85]

Fixes #1177.

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Pull Request Checklist

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Testing

• Unit test and/or integration test added
• Toolkit change?: integration tests manually executed (paste output to the PR description)
• Init template change?: coordinated update of integration tests (currently maintained in a private repo).

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• README: README and/or documentation topic updated
• jsdocs: All public APIs documented

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[eladb]

tiny test?

[skinny85]

It will be tested quite extensively when we use it - I'm not sure it's worth a separate test :).

[skinny85]

Your silence broke me @eladb . Added a test.

[RomainMuller]

I think it'd be nice if it was possible to have an integration test for this...

[skinny85]

I think it'd be nice if it was possible to have an integration test for this...

We will have them when we use this in the Lambda library :)