Update phpunit/phpunit requirement in the dev-dependencies group

Updates the requirements on [phpunit/phpunit](https://github.com/sebastianbergmann/phpunit) to permit the latest version.

Updates `phpunit/phpunit` to 11.4.4
- [Release notes](https://github.com/sebastianbergmann/phpunit/releases)
- [Changelog](https://github.com/sebastianbergmann/phpunit/blob/11.4.4/ChangeLog-11.4.md)
- [Commits](sebastianbergmann/phpunit@9.5.0...11.4.4)

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

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

Author: dependabot[bot]

composer.json

@@ -108,7 +108,7 @@
         "phpstan/phpstan": "^1.5",
         "thecodingmachine/phpstan-strict-rules": "^1.0",
         "squizlabs/php_codesniffer": "^3.2",
-        "phpunit/phpunit": "^9.5"
+        "phpunit/phpunit": "^11.4"
     },
     "scripts": {
         "phpstan": "phpstan analyse lib -c phpstan.neon --level=max --no-progress -vvv",