re-adding webpack-dev-server

Author: weaverryan

package.json

@@ -49,6 +49,7 @@
     "webpack": "^4.0.0",
     "webpack-chunk-hash": "^0.6.0",
     "webpack-cli": "^2.1.3",
+    "webpack-dev-server": "^3.1.4",
     "webpack-manifest-plugin": "^2.0.2",
     "yargs": "^8.0.1"
   },