Update phpunit/phpunit requirement from ^9.5 to ^11.4

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/11.4.3/ChangeLog-11.4.md)
- [Commits](sebastianbergmann/phpunit@9.5.0...11.4.3)

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

Signed-off-by: dependabot[bot] <support@github.com>

composer.json

@@ -14,7 +14,7 @@
 		"php": ">=7.4"
 	},
 	"require-dev": {
-		"phpunit/phpunit": "^9.5",
+		"phpunit/phpunit": "^11.4",
 		"donatj/drop": "^1.0",
 		"friendsofphp/php-cs-fixer": "^3.14",
 		"ext-dom": "*"