Fix grep command to find kubernetes api URL in documentation

What does this MR do?

Fix grep command to find kubernetes api URL in documentation

For current versions of kubernetes clusters I have, minikube/eks 1.18 command kubectl return something like

$ kubectl cluster-info
Kubernetes control plane is running at https://192.168.99.133:8443
KubeDNS is running at https://192.168.99.133:8443/api/v1/namespaces/kube-system/services/kube-dns:dns/proxy

and previous command do not return api url

I've added "Kubernetes control plane" inside of grep command and now it works

Screenshots (strongly suggested)

Does this MR meet the acceptance criteria?

Conformity

• Documentation (if required)