Bug#1055372: btrfs-progs: new upstream version

[Christoph Anton Mitterer]

Hey.

Upstream has released 6.6.1, which contains an important fix.

6.6 should not be used, see:
https://lore.kernel.org/linux-btrfs/20231105222046.19483-1-dste...@suse.com/T/#u

Cheers,
Chris.