[Tails-l10n] Release schedule for Tails 6.1

Hi,

We have no yet decided who will be the RM for Tails 6.1.

The current plan is:
- Monday, 2024-03-25: build images, start testing
- Tuesday, 2024-03-26: releasing

@testers, please let the RM know how much time you'll have for manual QA
from Monday 17:00 to Tuesday 11:00 (Europe/Berlin)!

Cheers!