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

4 jobs for abderrahim/new-cache-34 in 50 minutes and 38 seconds (queued for 2 seconds)
Status Job ID Name Coverage
  Build
passed #793823
gnome-build-meta aarch64
build-gnome-core-aarch64

00:39:48

passed #793824
gnome-build-meta armhf
build-gnome-core-arm

00:22:38

passed #793822
gnome-build-meta x86_64
build-gnome-core-i386

00:10:04

passed #793821
gnome-build-meta x86_64
build-gnome-core-x86_64

00:20:17