Bump phpunit/phpunit from 10.2.6 to 10.3.1

Bumps [phpunit/phpunit](https://github.com/sebastianbergmann/phpunit) from 10.2.6 to 10.3.1.
- [Changelog](https://github.com/sebastianbergmann/phpunit/blob/10.3.1/ChangeLog-10.3.md)
- [Commits](sebastianbergmann/phpunit@10.2.6...10.3.1)

---
updated-dependencies:
- dependency-name: phpunit/phpunit
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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