[Tails-l10n] Release schedule for Tails 7.3

Hi,

It's not clear yet who will be the RM for Tails 7.3.

The current plan is:

- Wednesday, December 10: build images, start testing
- Thursday, December 11: release

Developers, please:

  - Book time for automated and manual QA during office hours,
    from Wednesday 13:00 to Thursday 11:00 (Europe/Berlin).
    If you can't, please let the RM know.

  - During these 2 days, don't push any change to the branch
    used for the release.

Cheers,
--
intrigeri