add minimal readme bit about upstream_remotes

README.md

@@ -780,7 +780,10 @@ If multiple uploader tasks are specified, the tasks will run sequentially (vs in
  "size_excludes": [
  "downloads/*"
  ],
- "service_account_path":"/home/user/config/cloudplow/service_accounts/"
+ "service_account_path":"/home/user/config/cloudplow/service_accounts/",
+ "upstream_remotes": [
+ "some-remote"
+ ]
  }
 }
 ```
@@ -807,6 +810,7 @@ In the example above, the uploader references `"google"` from the `remotes` sect
 
  - This is currently not supported with sync operations.
 
+`"upstream_remotes"`: List of upstream remotes (crypt or union) that are going to get the Service Account rotation.
 
 ### Mover