cirrus: Use FreeBSD 11.4.

Support cycle of 11.3 ends in the end of September 2020,
so we need to upgrade.

Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Signed-off-by: 0-day Robot <robot@bytheb.org>

.cirrus.yml

@@ -3,7 +3,7 @@ freebsd_build_task:
   freebsd_instance:
     matrix:
       image_family: freebsd-12-1-snap
-      image_family: freebsd-11-3-snap
+      image_family: freebsd-11-4-snap
     cpu: 4
     memory: 8G