Update dependency phpunit/phpunit to v12

Author: renovate[bot]

composer.json

@@ -40,7 +40,7 @@
         "michelf/php-markdown": "^1.4 || ^2.0",
         "nyholm/psr7": "^1.5",
         "phpstan/phpstan": "^1.8.2",
-        "phpunit/phpunit": "^9.5.21 || ^10.5.9 || ^11.0.0",
+        "phpunit/phpunit": "^9.5.21 || ^10.5.9 || ^11.0.0 || ^12.0.0",
         "scrutinizer/ocular": "^1.8.1",
         "symfony/finder": "^5.3 | ^6.0 | ^7.0",
         "symfony/process": "^5.4 | ^6.0 | ^7.0",