Update webpack-dev-server

Author: dweber019

package.json

@@ -156,7 +156,7 @@
     "wait-on": "2.0.2",
     "wallaby-webpack": "0.0.37",
     "webpack": "2.2.1",
-    "webpack-dev-server": "2.3.0",
+    "webpack-dev-server": "2.4.2",
     "webpack-notifier": "1.5.0"
   }
 }