Allow newer versions of grumphp

Author: omarlopesino

composer.json

@@ -25,7 +25,7 @@
         "phpstan/extension-installer": "^1.2",
         "phpstan/phpstan": "^1.10",
         "phpstan/phpstan-deprecation-rules": "^1.1",
-        "phpro/grumphp": "^1.1",
+        "phpro/grumphp": "^1.1 || ^2.8",
         "metadrop/composer-comments": "^1.0",
         "metadrop/grumphp-php-compatibility": "^1.0",
         "drupal/image_styles_generator": "^1.0",