Spool holder cap for Prusa Core One

A simple cap that attaches to the default spool holder of the Prusa Core One to prevent filament spools from falling off.

Annoyingly, I've had this problem with one filament, which is a bit tangled up on the spool and vibrates quite a lot. It's fallen off the holder twice already, so I created this cap to keep it in place.

My first contribution to the 3d printing community, happy to take on any feedback!