This is the latest stable OVN release. As per the git submodule
command the required OVS version is v3.2.0-20-g1d78a3f31. This OVN
version contains additional_chassis column it its schema that is
required for functional testing of [1].
[1] https://review.opendev.org/c/openstack/neutron/+/895402
Change-Id: Idb564c589bd8f790bfcacd1b665780834b8fc686
Signed-off-by: Jakub Libosvar <libosvar@redhat.com>