fix composer.json

composer.json

@@ -32,7 +32,7 @@
         "twig/extensions": "~1.0",
         "sonata-project/exporter": "~1.0",
         "sonata-project/block-bundle": "~2.2,>=2.2.7,<2.3",
-        "sonata-project/core-bundle": "~2.2,<2.3.1",
+        "sonata-project/core-bundle": "~2.2",
         "doctrine/common": "~2.2",
         "knplabs/knp-menu-bundle": ">=1.1.0,<3.0.0",
         "knplabs/knp-menu": ">=1.1.0,<3.0.0"