Bugfix: Show timezone location in `snapshots` output

Since restic 0.19.0, the `snapshots` command printed the current timezone when
listing snapshots. That label can change during the year, for example with
daylight saving time. Restic now prints the location name instead.

https://github.com/restic/restic/pull/21876
https://forum.restic.net/t/possible-bug-in-timezone-naming/10867