Update composer.json

Author: arturLitvinavicius

composer.json

@@ -17,7 +17,7 @@
         "symfony/console": "^4.4|^5.0",
         "symfony/stopwatch": "^4.4|^5.0",
         "symfony/finder": "^4.4|^5.0",
-        "symfony/serializer": "^4.4|^5.0",
+        "symfony/serializer": "^4.4|^5.0|^6.0",
         "symfony/cache": "^4.4|^5.0",
         "symfony/property-access": "^4.4|^5.0",
         "doctrine/annotations": "^1.6",