chore(package): update webpack-dev-server to version 2.3.0 (PatrickJS#1466)

https://greenkeeper.io/

Author: greenkeeperio-bot

package.json

@@ -147,7 +147,7 @@
  "url-loader": "^0.5.7",
  "webpack": "2.2.0",
  "webpack-dev-middleware": "^1.10.0",
- "webpack-dev-server": "2.2.1",
+ "webpack-dev-server": "2.3.0",
  "webpack-dll-bundles-plugin": "^1.0.0-beta.5",
  "webpack-merge": "~2.6.1"
  },