composer(deps-dev): Bump phpunit/phpunit from 8.5.32 to 9.5.28

Bumps [phpunit/phpunit](https://github.com/sebastianbergmann/phpunit) from 8.5.32 to 9.5.28.
- [Release notes](https://github.com/sebastianbergmann/phpunit/releases)
- [Changelog](https://github.com/sebastianbergmann/phpunit/blob/main/ChangeLog-8.5.md)
- [Commits](sebastianbergmann/phpunit@8.5.32...9.5.28)

---
updated-dependencies:
- dependency-name: phpunit/phpunit
  dependency-type: direct:development
  update-type: version-update:semver-major
...

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

composer.json

@@ -17,7 +17,7 @@
         "ergebnis/composer-normalize": "^2.29.0",
         "ergebnis/license": "^2.1.0",
         "ergebnis/php-cs-fixer-config": "^2.14.0",
-        "phpunit/phpunit": "^8.5.32",
+        "phpunit/phpunit": "^9.5.28",
         "psalm/plugin-phpunit": "~0.18.4",
         "vimeo/psalm": "^4.29.0"
     },