chore(deps-dev): bump @aws-sdk/rds-signer from 3.803.0 to 3.873.0

Bumps [@aws-sdk/rds-signer](https://github.com/aws/aws-sdk-js-v3/tree/HEAD/packages/rds-signer) from 3.803.0 to 3.873.0.
- [Release notes](https://github.com/aws/aws-sdk-js-v3/releases)
- [Changelog](https://github.com/aws/aws-sdk-js-v3/blob/main/packages/rds-signer/CHANGELOG.md)
- [Commits](https://github.com/aws/aws-sdk-js-v3/commits/v3.873.0/packages/rds-signer)

---
updated-dependencies:
- dependency-name: "@aws-sdk/rds-signer"
  dependency-version: 3.873.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]