[Tails-l10n] Release schedule for Tails 4.19

Hi,

Tails 4.19 is scheduled to be released on June 1.

anonym will be the RM if the release date change does not make
it impossible.

Manual testers, please let tails-rm@??? know if you can do manual
testing on:

- May 31, late afternoon CEST
- June 1st, morning CEST

Cheers!