chore(package): update winston to version 2.3.0

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -54,7 +54,7 @@
     "method-override": "^2.3.5",
     "mongoose": "4.6.5",
     "morgan": "1.7.0",
-    "winston": "2.2.0"
+    "winston": "2.3.0"
   },
   "devDependencies": {
     "babel-cli": "6.18.0",