kubernetes release does not work with current 1.30

[tormath1]

Description

I tried to generate sysext image for Kubernetes 1.30 but it fails:

$ KBS_VERS=$(curl -fsSL --retry-delay 1 --retry 60 --retry-connrefused \
                --retry-max-time 60 --connect-timeout 20  \
                https://raw.githubusercontent.com/kubernetes/website/main/data/releases/schedule.yaml \
                | yq -r '.schedules[].previousPatches[0].release' \
                | awk '{print "kubernetes-v"$1}')
$ echo $KBS_VERS
kubernetes-vnull kubernetes-v1.29.3 kubernetes-v1.28.8 kubernetes-v1.27.12

Impact

Can't generate Kubernetes release when there is no previousPatches release