utils/checkpackagelib: run unit tests on GitLab CI
... so we can catch regressions on check-package.
Update to the new docker image that was pushed after the previous
commit.
Signed-off-by: Ricardo Martincoski <ricardo.martincoski@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>