Update webpack to the version 4

Author: DominikPalo

package.json

@@ -38,7 +38,7 @@
     "rimraf": "^2.5.2",
     "semistandard": "^7.0.5",
     "style-loader": "^0.13.1",
-    "webpack": "^1.13.0"
+    "webpack": "^4.20.2"
   },
   "dependencies": {
     "escape-string-regexp": "^1.0.5",