Update software apps to new appstream-generator format
gnome-software had some bugs that had to be solved for the new format123. I have cherry-picked the relevant commits, all of which have already been merged upstream and will be available in GNOME 42.
In gnome-software the format for external appstream files has been changed. The application will not do the data migration, but instead we have to take care of cleaning-up old files. See background discussion.
Edited by Pablo Correa Gomez