Creates an RSS feed of my read items from Readwise Reader.
Reader docs here: https://readwise.io/reader_api
In order to get read items from Readwise Reader -> Workflowy, this turns the read items (aka "archive") into an RSS feed, which Zapier picks up, and creates bullets in Workflowy.
Ideally would store the generated RSS or the last fetch date, and only get new items, but for now readwiseReaderDocumentList re-fetches the full history each time.
