deskutils/latte-dock: update to 0.9.12, latest upstream release

The existing latte-dock release, 0.9.11, isn't compatible
with upcoming KDE Plasma 5.22, so there's been a new
sort-of-release
https://psifidotos.blogspot.com/2021/05/latte-bug-fix-release-v0912.html

This release is compatible with the Plasma release in FreeBSD
ports and also comes with some new translations.