Require PHPStan 2.1 or newer

Author: stevegrunwell

composer.json

@@ -22,7 +22,7 @@
     "require-dev": {
         "dealerdirect/phpcodesniffer-composer-installer": "^1.0",
         "phpcompatibility/php-compatibility": "^9.3",
-        "phpstan/phpstan": "^1.10",
+        "phpstan/phpstan": "^2.1",
         "squizlabs/php_codesniffer": "^3.7",
         "symfony/phpunit-bridge": "^5.2 || ^6.2 || ^7.0"
     },