Allow jms/serializer-bundle 3.x

Author: EmmanuelVella

composer.json

@@ -12,7 +12,7 @@
     "require": {
         "php": "^7.1",
         "symfony-cmf/resource-bundle": "^1.0",
-        "jms/serializer-bundle": "^1.0 | ^2.0",
+        "jms/serializer-bundle": "^1.0 | ^2.0 | ^3.0",
         "symfony/translation": "^2.8 || ^3.3 || ^4.0"
     },
     "require-dev": {