chore(package): update webpack-merge to version 2.6.0

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -112,7 +112,7 @@
     "webpack-dev-middleware": "1.9.0",
     "webpack-dev-server": "2.2.0",
     "webpack-dll-bundles-plugin": "^1.0.0-beta.5",
-    "webpack-merge": "2.4.0"
+    "webpack-merge": "2.6.0"
   },
   "scripts": {
     "rimraf": "rimraf",