Bump phpunit/phpunit from 8.5.49 to 8.5.52 in /tools

Bumps [phpunit/phpunit](https://github.com/sebastianbergmann/phpunit) from 8.5.49 to 8.5.52.
- [Release notes](https://github.com/sebastianbergmann/phpunit/releases)
- [Changelog](https://github.com/sebastianbergmann/phpunit/blob/8.5.52/ChangeLog-8.5.md)
- [Commits](sebastianbergmann/phpunit@8.5.49...8.5.52)

---
updated-dependencies:
- dependency-name: phpunit/phpunit
  dependency-version: 8.5.52
  dependency-type: direct:development
...

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Author: dependabot[bot]