[cyborg][zun][masakari][tacker][venus] Pending removal of LegacyEngineFacade

o/ Just a heads up to the listed projects that oslo.db's LegacyEngineFacade is pending removal in the Epoxy cycle. I would encourage you to migrate asap to avoid a broken CI. For a minimal example of how to do this, I'd encourage you to look at [1]. Cheers, Stephen [1] https://review.opendev.org/c/openstack/mistral/+/926420