Bump php-stubs/wordpress-tests-stubs from 6.7.2 to 6.8.0 (#1177)

Bumps [php-stubs/wordpress-tests-stubs](https://github.com/php-stubs/wordpress-tests-stubs) from 6.7.2 to 6.8.0.
- [Commits](php-stubs/wordpress-tests-stubs@v6.7.2...v6.8.0)

---
updated-dependencies:
- dependency-name: php-stubs/wordpress-tests-stubs
  dependency-version: 6.8.0
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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