Merge pull request #729 from parity-js/dependabot/npm_and_yarn/extract-loader-4.0.3

Author: dependabot-preview[bot]

package-lock.json

@@ -120,7 +120,7 @@
     "eslint-plugin-react": "7.18.0",
     "eslint-plugin-standard": "4.0.1",
     "express": "4.17.1",
-    "extract-loader": "3.1.0",
+    "extract-loader": "4.0.3",
     "extract-text-webpack-plugin": "3.0.2",
     "file-loader": "2.0.0",
     "flow-bin": "^0.114.0",