chore(deps): update dependency phpunit/phpunit to v11.5.21

Author: renovate[bot]

composer.json

@@ -40,7 +40,7 @@
         "phpstan/phpstan-deprecation-rules": "^1.0.0",
         "phpstan/phpstan-phpunit": "^1.1.0",
         "phpstan/phpstan-strict-rules": "^1.1.0",
-        "phpunit/phpunit": "11.2.3",
+        "phpunit/phpunit": "11.5.21",
         "psr/http-client": "^1.0",
         "psr/http-factory": "^1.0",
         "psr/http-message": "^2.0",