drm/ci: python-artifacts: use shallow clone

drm/ci: python-artifacts: use shallow clone

The python-artifacts job has a timeout of 10 minutes, which causes
build failures as it was unable to clone the repository within the
specified limits. Set GIT_DEPTH to 10 to speed up cloning and avoid
build failures due to timeouts when fetching the full repository.

Acked-by: Daniel Stone <daniels@collabora.com>
Acked-by: Helen Koike <helen.fornazier@gmail.com>
Signed-off-by: Vignesh Raman <vignesh.raman@collabora.com>
Signed-off-by: Rob Clark <robin.clark@oss.qualcomm.com>