Update the Debian stable release to forky

Description

Update Debian stable release to forky, once it's released.

Update the latest tag on Debian images pointing to forky, once it's released (at onion-services/containers.yml.
Create a ticket for the next stable release (setting due dates so we can track this properly), and so on.
Or maybe find a way to derive this information from debian-distro-info --stable from the distro-info package, so this gets automated.