feature: support symfony/serializer 7.x (#1118)

Author: deguif

composer.json

@@ -32,7 +32,7 @@
         "symfony/http-kernel": "^3.0 || ^4.0 || ^5.0 || ^6.0 || ^7.0",
         "symfony/options-resolver": "^3.0 || ^4.0 || ^5.0 || ^6.0 || ^7.0",
         "symfony/security-core": "^3.0 || ^4.0 || ^5.0 || ^6.0 || ^7.0",
-        "symfony/serializer": "^3.0 || ^4.0 || ^5.0 || ^6.0",
+        "symfony/serializer": "^3.0 || ^4.0 || ^5.0 || ^6.0 || ^7.0",
         "twig/twig": "^2.14 || ^3.0"
     },
     "require-dev": {