Fixed dependency exproter v1.1.*

Fixed composer.json to be compatible with exporter v1.1.0

composer.json

@@ -28,7 +28,7 @@
         "twig/twig": ">=1.10,<2.0-dev",
         "knplabs/knp-menu-bundle": ">=1.1.0,<2.0.x-dev",
         "sonata-project/jquery-bundle": "dev-master",
-        "sonata-project/exporter": "dev-master",
+        "sonata-project/exporter": "1.1.*",
         "sonata-project/block-bundle": "dev-master"
     },
     "require-dev": {