Require PHPStan 2.1 (#832)

Author: mglaman

composer.json

@@ -11,7 +11,7 @@
     ],
     "require": {
         "php": "^8.1",
-        "phpstan/phpstan": "^2.0",
+        "phpstan/phpstan": "^2.1",
         "phpstan/phpstan-deprecation-rules": "^2.0",
         "symfony/finder": "^6.2 || ^7.0",
         "symfony/yaml": "^6.2 || ^7.0",