Temporary allow dev for CoreBundle

Author: wouterj

composer.json

@@ -17,7 +17,7 @@
         "symfony/framework-bundle": "^2.8|^3.0"
     },
     "require-dev": {
-        "symfony-cmf/core-bundle": "^2.0",
+        "symfony-cmf/core-bundle": "^2.0@dev",
         "symfony-cmf/testing": "^2.0",
         "doctrine/phpcr-odm": "^1.4|^2.0",
         "symfony/phpunit-bridge": "^3.2",