GitLab

A default git depth of 1 means git describe won't work, let's set it to
something high enough that we should always have at least one tag in the
history.

And save the artifacts after the coverity compilation, where the submission
fails for whatever reason we can just resubmit those manually without having
to rebuild the whole image locally.
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>