Fix version20 input to match reality, remove version21rc
Fix version20 input to match reality, remove version21rc

GoogleContainerTools/skaffold,GoogleContainerTools/skaffold,GoogleContainerTools/skaffold,GoogleContainerTools/skaffold,GoogleContainerTools/skaffold,GoogleContainerTools/skaffold,GoogleContainerTools/skaffold,GoogleContainerTools/skaffold,GoogleContainerTools/skaffold