caltechlibrary/pokapi: Release 0.2.1

Fixes in this release: * Fix: `Folio.record(...)` is supposed to throw a `NotFound` exception if it can't find the requested item. (It was returning a blank `FolioRecord` object.) * Fix: the fields in the definition of `FolioRecord` were out of date with the most recent code and documentation. * Fix: use a fallback method to get the author names from the title string instead of setting it to `None`. * Add acknowledgment for the artwork used for the icon.