fix(package): update webpack to version 4.29.3

Closes #19

Author: greenkeeper[bot]

package.json

@@ -18,7 +18,7 @@
     "babel-preset-env": "^1.6.1",
     "babel-polyfill": "^6.26.0",
     "happypack": "^4.0.1",
-    "webpack": "2.7.0"
+    "webpack": "4.29.3"
   },
   "scripts": {
     "lint": "rispa-eslint .",