chore(package): update webpack-dev-server to version 3.8.2

Closes #54

Author: greenkeeper[bot]

package.json

@@ -94,7 +94,7 @@
     "vue-template-compiler": "^2.5.17",
     "webpack": "^4.28.0",
     "webpack-bundle-analyzer": "^2.13.1",
-    "webpack-dev-server": "^2.9.1",
+    "webpack-dev-server": "^3.8.2",
     "webpack-merge": "^4.1.4"
   },
   "engines": {