Out of date mirrors
If a mirror is present for all versions except the release version
such as https://mirror2.sandyriver.net/pub/software/gimp/pub/gimp/ ,
then should tools/downloads/gimp-check-mirrors.py
consider it a
failure or should we remove the mirror as incomplete?
Currently, every test pipeline for gimp-web
is failing due to
cases like these, which means it's not helpful for commits that break
other things here.