Upgrade to Symfony 6 (#17)

* Upgrade to Symfony 6

* Fix version constraints

* Fix the fix

Author: szepeviktor

composer.json

@@ -25,13 +25,13 @@
     "require": {
         "php": "^7.3 || ^8.0",
         "nikic/php-parser": "^4.10",
-        "symfony/console": "^5.1",
-        "symfony/filesystem": "^5.0",
-        "symfony/finder": "^5.0"
+        "symfony/console": "^5.1 || ^6.0",
+        "symfony/filesystem": "^5.0 || ^6.0",
+        "symfony/finder": "^5.0 || ^6.0"
     },
     "require-dev": {
         "vimeo/psalm": "^4.1",
         "phpunit/phpunit": "^9.4",
-        "friendsofphp/php-cs-fixer": "^2.16"
+        "friendsofphp/php-cs-fixer": "^2.16 || ^3.12"
     }
 }