Update phpunit/phpunit requirement from ^9.5.28 to ^11.5.1

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/11.5.1/ChangeLog-11.5.md)
- [Commits](sebastianbergmann/phpunit@9.5.28...11.5.1)

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

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

composer.json

@@ -21,7 +21,7 @@
         "ext-redis": "*",
         "ext-memcached": "*",
         "bamarni/composer-bin-plugin": "^1.4",
-        "phpunit/phpunit": "^9.5.28"
+        "phpunit/phpunit": "^11.5.1"
     },
     "autoload": {
         "psr-4": {