chore(rds): support RDS for PostgreSQL 16.1 and 15.5

[go-to-k]

This PR supports RDS for PostgreSQL 16.1 and 15.5.

❯ aws rds describe-db-engine-versions \
∙   --engine postgres \
∙   --query "DBEngineVersions[?EngineVersion=='16.1'||EngineVersion=='15.5'].[DBEngineVersionDescription,EngineVersion,DBParameterGroupFamily,MajorEngineVersion,Status]"

[
    [
        "PostgreSQL 15.5-R1",
        "15.5",
        "postgres15",
        "15",
        "available"
    ],
    [
        "PostgreSQL 16.1-R1",
        "16.1",
        "postgres16",
        "16",
        "available"
    ]
]

https://aws.amazon.com/about-aws/whats-new/2023/11/amazon-rds-postgresql-major-version-16/

---

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

[aws-cdk-automation]

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• Commit ID: 5a3e6ec
• Result: SUCCEEDED
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[srshkmr]

Looks good!

[watany-dev]

15.5

https://aws.amazon.com/jp/about-aws/whats-new/2023/11/amazon-rds-postgresql-minor-versions-15-5-14-10-13-13-12-17-11-22/

[mergify]

Thank you for contributing! Your pull request will be updated from main and then merged automatically (do not update manually, and be sure to allow changes to be pushed to your fork).