Merge pull request #21 from pine/greenkeeper/webpack-4.20.0

Update webpack to the latest version 🚀

Author: pine

package.json

@@ -31,7 +31,7 @@
     "mocha": "^5.0.0",
     "npm-run-all": "^4.1.2",
     "text-encoding": "^0.7.0",
-    "webpack": "4.18.1",
+    "webpack": "4.20.0",
     "webpack-cli": "^3.1.1"
   },
   "author": {