No container image of v1.8.0

[jenting]

There is no container image of v1.8.0, which means I can't pull image from k8s.gcr.io/cloud-provider-gcp/gcp-compute-persistent-disk-csi-driver:v1.8.0

[jenting]

cc @mattcary

[mattcary]

After the image is cut, the cloud build pipeline needs to create an image, then it needs to be promoted from staging, see kubernetes/k8s.io#4294.

It takes a few days for this process to work out.

/close