ci: use the latest image
Identified, since there are some fixes in gi-docgen that don't seem to be available in the online docs.
Ref: https://github.com/flatpak/flatpak/pull/5688#discussion_r1488777994
Identified, since there are some fixes in gi-docgen that don't seem to be available in the online docs.
Ref: https://github.com/flatpak/flatpak/pull/5688#discussion_r1488777994