chore(package): update webpack to version 4.1.1

Closes #33

Author: greenkeeper[bot]

Diff for: package.json

@@ -59,7 +59,7 @@
         "prettier": "^1.5.2",
         "remark-cli": "^4.0.0",
         "remark-preset-lint-itgalaxy": "^7.0.0",
-        "webpack": "^3.0.0",
+        "webpack": "^4.1.1",
         "webpack-dev-middleware": "^1.0.0",
         "webpack-hot-middleware": "^2.0.0"
     },