Avocado will, by default, produce JUnit files.  Let's ask GitLab
to present those in the web UI.

Signed-off-by: Cleber Rosa <crosa@redhat.com>
Message-Id: <20201009205513.751968-4-crosa@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>