chore(deps): update dependency webpack to v4.18.1

Author: renovate-bot

package.json

@@ -81,7 +81,7 @@
     "semver": "5.5.1",
     "serve-static": "1.13.2",
     "uglifyjs-webpack-plugin": "1.3.0",
-    "webpack": "4.18.0",
+    "webpack": "4.18.1",
     "webpack-cli": "3.1.0"
   },
   "peerDependencies": {