rolling back webpack-dev-midddleware 2.0, as it's node6+

Author: shellscape

package-lock.json

@@ -66,7 +66,7 @@
     "spdy": "^3.4.1",
     "strip-ansi": "^4.0.0",
     "supports-color": "^5.1.0",
-    "webpack-dev-middleware": "^2.0.3",
+    "webpack-dev-middleware": "1.12.2",
     "yargs": "^10.0.3"
   },
   "devDependencies": {