Merge pull request GoogleChromeLabs#612 from GoogleChromeLabs/renovate/file-loader-4.x

Update dependency file-loader to v4

Author: surma

package-lock.json

@@ -34,7 +34,7 @@
     "escape-string-regexp": "2.0.0",
     "exports-loader": "0.7.0",
     "file-drop-element": "0.2.0",
-    "file-loader": "3.0.1",
+    "file-loader": "4.0.0",
     "gzip-size": "5.1.1",
     "html-webpack-plugin": "3.2.0",
     "husky": "2.3.0",