Update phpunit/phpunit requirement from ^9.6 to ^11.2

Updates the requirements on [phpunit/phpunit](https://github.com/sebastianbergmann/phpunit) to permit the latest version.
- [Release notes](https://github.com/sebastianbergmann/phpunit/releases)
- [Changelog](https://github.com/sebastianbergmann/phpunit/blob/11.2.6/ChangeLog-11.2.md)
- [Commits](sebastianbergmann/phpunit@9.6.0...11.2.6)

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

Signed-off-by: dependabot[bot] <[email protected]>

composer.json

@@ -28,7 +28,7 @@
         "symfony/http-kernel": "^5.4 || ^6.0 || ^7.0"
     },
     "require-dev": {
-        "phpunit/phpunit": "^9.6"
+        "phpunit/phpunit": "^11.2"
     },
     "config": {
         "bin-dir": "bin",