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

Closes #616

Author: greenkeeper[bot]

package.json

@@ -128,7 +128,7 @@
     "stylelint-scss": "3.13.0",
     "supertest": "4.0.2",
     "terser-webpack-plugin": "2.3.1",
-    "url-loader": "3.0.0",
+    "url-loader": "4.1.0",
     "webpack": "4.41.4",
     "webpack-cli": "3.3.10",
     "webpack-dev-server": "3.10.1"