chore(package): update redis to version 2.5.2

http://greenkeeper.io/

package.json

@@ -40,7 +40,7 @@
     "lwip": "~0.0.8",
     "mime": "~1.3.4",
     "node-df": "crafatar/node-df",
-    "redis": "~2.4.2",
+    "redis": "~2.5.2",
     "request": "~2.69.0",
     "toobusy-js": "~0.4.2"
   },