community/buffyboard: upgrade to 3.1.0
Buffyboard has moved into https://gitlab.com/postmarketOS/buffybox. Changes since the last packaged version are listed in https://gitlab.com/postmarketOS/buffybox/-/releases/3.0.0 and https://gitlab.com/postmarketOS/buffybox/-/releases/3.1.0.
CC @calebccff