Bump aws/aws-sdk-php from 3.257.5 to 3.257.6

Bumps [aws/aws-sdk-php](https://github.com/aws/aws-sdk-php) from 3.257.5 to 3.257.6.
- [Release notes](https://github.com/aws/aws-sdk-php/releases)
- [Commits](aws/aws-sdk-php@3.257.5...3.257.6)

---
updated-dependencies:
- dependency-name: aws/aws-sdk-php
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <support@github.com>