Allow Symfony 6

Author: LauLaman

composer.json

@@ -14,7 +14,7 @@
     "require": {
         "php": ">=7.1.0",
         "ext-json": "*",
-        "symfony/framework-bundle": "^2.7 || ^3.0 || ^4.0 || ^5.0",
+        "symfony/framework-bundle": "^2.7 || ^3.0 || ^4.0 || ^5.0 || ^6.0",
         "api-postcode/php-client": "^1.0"
     },
     "require-dev": {