chore(package): update webpack-dev-middleware to version 2.0.4

Closes #121

Author: greenkeeper[bot]

package.json

@@ -94,7 +94,7 @@
     "typescript": "~2.6.1",
     "url-loader": "^0.6.1",
     "webpack": "2.3.3",
-    "webpack-dev-middleware": "^1.12.0",
+    "webpack-dev-middleware": "^2.0.4",
     "webpack-dev-server": "2.9.3"
   },
   "engines": {