Remove k8s.io/client-go dependencies in go.mod

Please refer to https://github.com/kubernetes-sigs/gcp-compute-persistent-disk-csi-driver/pull/2170.

The steps are:
1. Remove the replace in go.mod
2. Run ``go mod graph | grep 'k8s.io/client-go'`` to see current versions being used
3. Analyze and remove client-go dependency