Fetch cached data from GitLab itself

Retrieving the published data can be complicated on downstream deployment where the data is auth protected.

Since GitLab stores it as an artifact accessible using the job token, use it to side-step the issue.

bin/packaging-data-fetch-downstream

@@ -399,6 +399,7 @@ if __name__ == "__main__":
     logging.basicConfig(level=args.loglevel or logging.INFO)
 
     if args.cache:
+        logging.info(f"Loading cacheable data from {args.cache.name}")
         yaml_import = yaml.safe_load(args.cache)
         try:
             cache = yaml_import["packages"]