feat(rds): add engineVersion to DatabaseCluster

[joehillen]

Without this change, CDK's RDS DatabaseCluster is not very useful
because you can only deploy the default versions
of the given database engine.

This change adds an optional prop engineVersion

fixes #2212

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Pull Request Checklist

• Testing
  • Unit test added (prefer not to modify an existing test, otherwise, it's probably a breaking change)
  • CLI change?: coordinate update of integration tests with team
  • cdk-init template change?: coordinated update of integration tests with team
• Docs
  • jsdocs: All public APIs documented
  • README: README and/or documentation topic updated
  • Design: For significant features, design document added to design folder
• Title and Description
  • Change type: title prefixed with fix, feat and module name in parens, which will appear in changelog
  • Title: use lower-case and doesn't end with a period
  • Breaking?: last paragraph: "BREAKING CHANGE: <describe what changed + link for details>"
  • Issues: Indicate issues fixed via: "Fixes #xxx" or "Closes #xxx"
• Sensitive Modules (requires 2 PR approvers)
  • IAM Policy Document (in @aws-cdk/aws-iam)
  • EC2 Security Groups and ACLs (in @aws-cdk/aws-ec2)
  • Grant APIs (only if not based on official documentation with a reference)

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

[agdimech]

+1 - I also need this change as I am trying to enable logical_replication which is only supported on postgres 10.6+ however the default instance type that is created is 9.6 :(

[joehillen]

@agdimech As a workaround in the meantime, you can copy the cluster.ts file from my branch and change the imports. That's what I'm doing.

[agdimech]

Haha I am already using it :p

Thanks for this!

[rix0rrr]

Thanks for the contribution! Unfortunately, I've just merged some other RDS changes that lead to a conflict. Could you please merge from master and resolve them?

[joehillen]

@rix0rrr Done. Rebased and force-pushed.

[rix0rrr]

I made a change directly to avoid a roundtrip. Hope I didn't break the build :)

[joehillen]

Thanks. Looks like you did not break the build.

[agdimech]

Has this change been merged into master or just your own dev branch?