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/11.3.1/ChangeLog-11.3.md)
- [Commits](sebastianbergmann/phpunit@9.5.0...11.3.1)

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

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

composer.json

@@ -23,7 +23,7 @@
         }
     },
     "require-dev": {
-        "phpunit/phpunit": "^9.5",
+        "phpunit/phpunit": "^11.3",
         "phpstan/phpstan": "^1.10",
         "squizlabs/php_codesniffer": "^3.5"
     },