Deprecate Geary PPA
After all of the headache releasing 0.13.0 on Bionic caused due to its older version of GLib, and with the UX changes in 3.32 looming, I think it's time to deprecate the official Geary PPA. If people using the PPA still want to get just-in-time updates, they should install Geary from Flathub.
We can keep the PPA up, and will publish updates to 0.13.x there, but this bug basically just means removing the /debian
directory and CI config from master.
Edited by Michael Gratton