update version to 0.5.0-SNAPSHOT

Author: dimichgh

package.json

@@ -9,7 +9,7 @@
         "email": "huzhou@ebay.com"
     }],
     "name": "cluster2",
-    "version": "0.5.0",
+    "version": "0.5.0-SNAPSHOT",
     "repository": {
         "type": "git",
         "url": "https://github.com/cubejs/cluster2"