build(deps-dev): bump pestphp/pest from 2.20.0 to 2.21.0 (#311)

Bumps [pestphp/pest](https://github.com/pestphp/pest) from 2.20.0 to 2.21.0.
- [Release notes](https://github.com/pestphp/pest/releases)
- [Changelog](https://github.com/pestphp/pest/blob/2.x/RELEASE.md)
- [Commits](pestphp/pest@v2.20.0...v2.21.0)

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

Signed-off-by: dependabot[bot] <support@github.com>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>