project.conf,.gitlab-ci.yml: Enable packet-specific cache

4 jobs for abderrahim/new-cache-36 in 44 minutes and 45 seconds
Status Job ID Name Coverage
  Build
passed #793806
gnome-build-meta aarch64
build-gnome-core-aarch64

00:44:44

passed #793807
gnome-build-meta armhf
build-gnome-core-arm

00:26:05

passed #793805
gnome-build-meta x86_64
build-gnome-core-i386

00:16:39

passed #793804
gnome-build-meta x86_64
build-gnome-core-x86_64

00:28:50