Overview
Currently the write.as desktop repo only has CI enabled for the elementary builds. I think it would be a good idea to enable flatpak CI builds as well, especially if we want to ship the flatpak to users via the write.as site.
Implementation
We will likely need to set up a custom docker image with the right SDK's installed. See https://gitlab.gnome.org/GNOME/gnome-runtime-images for an example.