Allow PHPStan ^2.0 (currently in development)

Author: ondrejmirtes

composer.json

@@ -9,7 +9,7 @@
     "require": {
         "php": "^7.2 || ^8.0",
         "composer-plugin-api": "^2.0",
-        "phpstan/phpstan": "^1.9.0"
+        "phpstan/phpstan": "^1.9.0 || ^2.0"
     },
     "require-dev": {
         "composer/composer": "^2.0",