chore(rds): add MySQL 8.0.42 and 8.4.5, Aurora Postgres 17.4 and deprecate 16.5, 17.1, 17.2

[phuhung273]

Issue # (if applicable)

None

Reason for this change

https://aws.amazon.com/about-aws/whats-new/2025/05/amazon-rds-mysql-new-minor-versions/
https://aws.amazon.com/about-aws/whats-new/2025/05/amazon-aurora-postgresql-major-version-17/

Description of changes

Instance engine add MySQL 8.0.42 and 8.4.5
Cluster engine add Postgres 17.4 and deprecate 16.5, 17.1, 17.2

Description of how you validated changes

$ aws rds describe-db-engine-versions --engine aurora-postgresql --output table --query 'DBEngineVersions[*].{Engine:Engine,EngineVersion:EngineVersion}'
|  aurora-postgresql |  16.1            |
|  aurora-postgresql |  16.2            |
|  aurora-postgresql |  16.3            |
|  aurora-postgresql |  16.4            |
|  aurora-postgresql |  16.4-limitless  |
|  aurora-postgresql |  16.6            |
|  aurora-postgresql |  16.6-limitless  |
|  aurora-postgresql |  16.8            |
|  aurora-postgresql |  17.4            |

Checklist

• My code adheres to the CONTRIBUTING GUIDE and DESIGN GUIDELINES

---

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

[phuhung273]

Thank you @mazyu36

[paulhcsun]

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• CodeBuild project: AutoBuildv2Project1C6BFA3F-wQm2hXv2jqQv
• Commit ID: 73e90cf
• Result: SUCCEEDED
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