Support Symfony 6.x options resolver

Author: endroid

composer.json

@@ -15,7 +15,7 @@
         "psr/cache": "^1.0 || ^2.0",
         "php-http/client-common": "^1.9 || ^2.0",
         "php-http/message-factory": "^1.0",
-        "symfony/options-resolver": "^2.6 || ^3.0 || ^4.0 || ^5.0"
+        "symfony/options-resolver": "^2.6 || ^3.0 || ^4.0 || ^5.0 || ^6.0"
     },
     "require-dev": {
         "phpspec/phpspec": "^5.1 || ^6.0"