gitlab-ci: Don't cache object files.
gitlab-ci: Don't cache object files.

This could only help with the initial build, not `make distcheck`
and since config.h is generated fresh for each job, everything
was remade anyway. Thanks to ePirat for pointing out the issue.

ShiftMediaProject/vorbis,ShiftMediaProject/vorbis,ShiftMediaProject/vorbis,ShiftMediaProject/vorbis,ShiftMediaProject/vorbis,ShiftMediaProject/vorbis