Update dependency eslint-loader to v4

Author: renovate-bot

package.json

@@ -100,7 +100,7 @@
     "eslint": "6.8.0",
     "eslint-config-airbnb": "18.1.0",
     "eslint-config-prettier": "6.11.0",
-    "eslint-loader": "3.0.4",
+    "eslint-loader": "4.0.2",
     "eslint-plugin-import": "2.20.2",
     "eslint-plugin-jest": "23.8.2",
     "eslint-plugin-jsx-a11y": "6.2.3",