dependencies: Upgrade webpack-dev-server to 3.5.1 and install types.

package.json

@@ -8,6 +8,7 @@
     "@types/node": "8.0.34",
     "@types/underscore": "1.8.18",
     "@types/webpack": "4.4.32",
+    "@types/webpack-dev-server": "3.1.6",
     "blueimp-md5": "2.10.0",
     "clipboard": "2.0.4",
     "css-hot-loader": "1.3.9",
@@ -71,7 +72,7 @@
     "stylelint": "9.3.0",
     "svgo": "1.2.2",
     "swagger-parser": "3.4.1",
-    "webpack-dev-server": "3.1.4",
+    "webpack-dev-server": "3.5.1",
     "xmlhttprequest": "1.8.0"
   },
   "scripts": {