fix(s3-deployment): CallerReference has to be unique

[hoegertn]

fixes #3878

CallerReference has to be unique per invalidation but was set to a fix value for every deployment.

This PR fixes this.

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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

[mergify]

Pull Request Checklist

• Testing

• Unit test added (prefer to add a new test rather than modify existing tests)
• CLI change? Re-run/add CLI integration tests

• Documentation

• Inline docs: make sure all public APIs are documented (copy & paste from official AWS docs)
• README: update module README
• Design: for significant features, follow the design process

• Title uses the format type(scope): text

• Type: fix, feat, refactor go into CHANGELOG, chore is hidden
• Scope: name of the module without the aws- or cdk- prefix or postfix (e.g. s3 instead of aws-s3-deployment)
• Style: use all lower-case, do not end with a period

• Description

• Rationale: describe rationale of change and approach taken
• Issues: Indicate issues fixed via: fixes #xxx or closes #xxx
• Breaking?: last paragraph: BREAKING CHANGE: <describe what changed + link for details>

• Sensitive Modules (requires 2 PR approvers)

• IAM document library (in @aws-cdk/aws-iam)
• EC2 security groups and ACLs (in @aws-cdk/aws-ec2)
• Grant APIs (if not based on official documentation with a reference)

[shivlaks]

do the tests for this Lambda need to be updated as well?

[mergify]

Codebuild (Continuous Integration) build failed for current commits. Please check log and resolve before PR is merged.

[hoegertn]

do the tests for this Lambda need to be updated as well?

Good catch. I should be awake when creating PRs ;-)

[mergify]

Thank you for contributing! Your pull request is now being automatically merged.

[harmohan-a]

let me know when its released. i'll test it then

[eladb]

Can you please update the PR description with details on why this needed to change? What was wrong with the previous implementation, what the service requires and how this fixes it. Please try to follow the PR checklist above.