Bug#1087386: minetest: upstream has been renamed to Luanti with release version 5.10.0

[Travis Wrightsman]

I have started working on updating the package to 5.10 and performing
the necessary renames in an MR [0] on Salsa. It is still very
preliminary.

Cheers,
Travis

[0] https://salsa.debian.org/games-team/minetest/-/merge_requests/7