Add tempest-artifacts to gitignore

Author: Alex-Welsh

.gitignore

@@ -55,3 +55,6 @@ etc/kayobe/environments/aufn-ceph/kolla/config/cinder/ceph.conf
 etc/kayobe/environments/aufn-ceph/kolla/config/cinder/ceph.client.glance.keyring
 etc/kayobe/environments/aufn-ceph/kolla/config/nova/ceph.conf
 etc/kayobe/environments/aufn-ceph/kolla/config/nova/ceph.client.glance.keyring
+
+# Tempest logs
+tempest-artifacts