minor: upgrade PHPStan

Author: kbond

composer.json

@@ -14,7 +14,7 @@
         "php": ">=8.1"
     },
     "require-dev": {
-        "phpstan/phpstan": "^1.4",
+        "phpstan/phpstan": "^2.0",
         "phpunit/phpunit": "^9.6.19",
         "symfony/phpunit-bridge": "^6.4|^7.0|^8.0",
         "symfony/var-dumper": "^6.4|^7.0|^8.0"