Bump aws/aws-sdk-php from 3.278.3 to 3.300.15

Bumps [aws/aws-sdk-php](https://github.com/aws/aws-sdk-php) from 3.278.3 to 3.300.15.
- [Release notes](https://github.com/aws/aws-sdk-php/releases)
- [Commits](aws/aws-sdk-php@3.278.3...3.300.15)

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

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