chore(deps-dev): bump php-stubs/wp-cli-stubs from 2.8.0 to 2.9.0

Bumps [php-stubs/wp-cli-stubs](https://github.com/php-stubs/wp-cli-stubs) from 2.8.0 to 2.9.0.
- [Commits](php-stubs/wp-cli-stubs@v2.8.0...v2.9.0)

---
updated-dependencies:
- dependency-name: php-stubs/wp-cli-stubs
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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