chore(package): update url-loader to version 4.1.0

Closes #30

Author: greenkeeper[bot]

package.json

@@ -44,7 +44,7 @@
     "tslint-loader": "^3.5.4",
     "typedoc": "^0.15.0",
     "typescript": "^3.1.6",
-    "url-loader": "^2.0.0",
+    "url-loader": "^4.1.0",
     "webpack": "^4.38.0",
     "webpack-cli": "^3.1.2",
     "webpack-dev-server": "^3.1.10",