Bump to phpstan ^2.1.8 (#465)

Author: samsonasik

composer.json

@@ -9,7 +9,7 @@
     "require-dev": {
         "rector/rector-src": "dev-main",
         "phpunit/phpunit": "^11.5",
-        "phpstan/phpstan": "^2.1",
+        "phpstan/phpstan": "^2.1.8",
         "phpecs/phpecs": "^2.0",
         "phpstan/extension-installer": "^1.4",
         "symplify/vendor-patches": "^11.3",