fix: etl/package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-AJV-15274295

Author: snyk-bot

etl/package.json

@@ -7,7 +7,7 @@
     "@rails/ujs": "^6.0.0",
     "@rails/webpacker": "5.4.3",
     "turbolinks": "^5.2.0",
-    "webpack": "^4.46.0",
+    "webpack": "^5.0.0",
     "webpack-cli": "^3.3.12"
   },
   "version": "0.1.0",