Revert PHPStan update

Author: Sephster

composer.json

@@ -15,8 +15,8 @@
     "require-dev": {
         "phpunit/phpunit": "^8.5.4 || ^9.1.3",
         "laminas/laminas-diactoros": "^2.3.0",
-        "phpstan/phpstan": "^0.12.19",
-        "phpstan/phpstan-phpunit": "^0.12.8",
+        "phpstan/phpstan": "^0.11.19",
+        "phpstan/phpstan-phpunit": "^0.11.2",
         "roave/security-advisories": "dev-master"
     },
     "repositories": [