[Tails-l10n] Release schedule for Tails 6.6

Hi,

intrigeri will be the RM for Tails 6.6

The current plan is:
- Monday, August 12: build images, start testing
- Tuesday, August 13: 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!