Release notes for Eventing 0.20.0

Known Issues

InMemoryChannel objects created before release 0.20 may have an extra finalizer that blocks their deletion. Use the script in #4512 (comment) to remove the finalizers.

Now setting the channel spec delivery field defaults every subscription to that particular delivery spec (#4652, @slinkydeveloper)

🐛 Allow scaling the in-memory Channel dispatcher without disabling high availability. (#4675, @antoineco)

🧹 Webhook no longer has Cluster-wide Secret permissions. Now the Webhook's Secret permissions are restricted to the knative-eventing namespace. (#4684, @Harwayne)

🐛 Fix bug #4715 (#4716, @vaikas)
Message receiver supports customized liveness and readiness check (#4707, @grac3gao)
You need to run the storage migration tool after the upgrade to migrate from v1beta1 to v1 apiserversources.sources.knative.dev resources. (#4655, @pierDipi)
You need to run the storage migration tool after the upgrade to migrate from v1beta1 to v1 containersources.sources.knative.dev resources. (#4657, @pierDipi)
You need to run the storage migration tool after the upgrade to migrate from v1beta1 to v1 sinkbindings.sources.knative.dev resources. (#4658, @pierDipi)