Bump phpro/grumphp from 2.8.0 to 2.9.0 in the dependencies group

Bumps the dependencies group with 1 update: [phpro/grumphp](https://github.com/phpro/grumphp).


Updates `phpro/grumphp` from 2.8.0 to 2.9.0
- [Release notes](https://github.com/phpro/grumphp/releases)
- [Commits](phpro/grumphp@v2.8.0...v2.9.0)

---
updated-dependencies:
- dependency-name: phpro/grumphp
  dependency-type: direct:development
  update-type: version-update:semver-minor
  dependency-group: dependencies
...

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