docs: use label match in SERVICECIDR command for KinD

Use `component=kube-apiserver` match in doc command for KinD clusters

- Named KinD clusters will have kube-apiserver pods with the cluster name included--the format is `kube-apiserver-<CLUSTERNAME>-control-plane`.  The kube-system control-plane uses the label `component=kube-apiserver` on the apiserver pods.

Fixes #3182

Signed-off-by: Tim Swanson <[email protected]>

docs/content/en/docs/getting-started/network.md

@@ -31,7 +31,7 @@ export SERVICECIDR=$(gcloud container clusters describe ${NAME} --zone ${ZONE} |
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-export SERVICECIDR=$(kubectl describe pod -n kube-system kube-apiserver-kind-control-plane | awk -F= '/--service-cluster-ip-range/ {print $2; }')
+export SERVICECIDR=$(kubectl describe pod -n kube-system -l component=kube-apiserver | awk -F= '/--service-cluster-ip-range/ {print $2; }')
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