:dizzy: Adding k8s 1.21, dropping 1.18 and updates to 1.19 and 1.20 line :lipstick: (#5480)
:dizzy: Adding k8s 1.21, dropping 1.18 and updates to 1.19 and 1.20 line :lipstick: (#5480)

Signed-off-by: Matthias Wessendorf <8046805a262331760c6cd2411c7603ff9641e112@redhat.com>
knative/eventing,knative/eventing