composer(deps-dev): update phpunit/phpunit requirement

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

@@ -30,7 +30,7 @@
     },
     "require-dev": {
         "bamarni/composer-bin-plugin": "^1.8",
-        "phpunit/phpunit": "^9.6",
+        "phpunit/phpunit": "^11.2",
         "symfony/var-dumper": "^5.4"
     },
     "config": {