Ensure docker logout also on failure

If a image build fails it could happen that the builder is corrupted with Authenticating with credentials from C:\Users\Gitlab.docker\config.json. I guess this is because we do not run docker logout in such cases??? If that is true, this change should fix it.

Please note that I am not 100% sure if after_script run on failure? If not we need a different approach similar to https://invent.kde.org/sysadmin/ci-management/-/blob/master/.gitlab-ci.yml?ref_type=heads#L38