Rename local-gitlab-ci.yml into local-pre-source-build-gitlab-ci.yml

debian/apertis/local-gitlab-ci.yml is deprecated in favor of
debian/apertis/local-pre-source-build-gitlab-ci.yml to match
debian/apertis/local-post-source-build-gitlab-ci.yml

Signed-off-by: Dylan Aïssi <dylan.aissi@collabora.com>