Bump slevomat/coding-standard from 8.13.4 to 8.14.1 in /tools/phpcs

Bumps [slevomat/coding-standard](https://github.com/slevomat/coding-standard) from 8.13.4 to 8.14.1.
- [Release notes](https://github.com/slevomat/coding-standard/releases)
- [Commits](slevomat/coding-standard@8.13.4...8.14.1)

---
updated-dependencies:
- dependency-name: slevomat/coding-standard
  dependency-type: direct:development
  update-type: version-update:semver-minor
...

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