Fast DataPath released a new major version of Open vSwitch, which is 3.3.
This version is going to be a new LTS and contains performance improvements
and features required for future releases of OVN. Since OCP 4.16 is planned
to have a longer support time frame, it should use this version of OVS.
Moving to newer versions of OVS will also gradually allow FDP to drop support
for older streams not used by any layered products.

Most notable relevant improvements over OVS 3.1 are:
- Improved performance of database operations, most notbaly the initial read
  of the database file and the database schema conversion on updates.

The plan is to also update the main ovs-vwitchd on the os level in a separate
issue, this will provide support for flushing CT entries by marks and labels
needed for future versions of OVN.  And it's better to keep versions on the
host and inside the container in sync.

The change was discussed with FDP and OVS-QE.