chore(package): update webpack-dev-server to version 3.1.3

Closes #282

Author: greenkeeper[bot]

package.json

@@ -120,7 +120,7 @@
     "typescript": "^2.7.2",
     "uglifyjs-webpack-plugin": "^1.2.2",
     "webpack": "^3.11.0",
-    "webpack-dev-server": "^2.11.1",
+    "webpack-dev-server": "^3.1.3",
     "webpack-merge": "^4.1.2"
   },
   "ava": {