setup/independent: fix cilium installation guide for kubeadm

Signed-off-by: André Martins <[email protected]>

content/en/docs/setup/independent/create-cluster-kubeadm.md

@@ -308,6 +308,8 @@ kubectl apply -f https://docs.projectcalico.org/v3.3/getting-started/kubernetes/
 {{% tab name="Cilium" %}}
 For more information about using Cilium with Kubernetes, see [Kubernetes Install guide for Cilium](https://docs.cilium.io/en/stable/kubernetes/).
 
+For `cilium` to work correctly, you must pass `--pod-network-cidr=10.217.0.0/16` to `kubeadm init`.
+
 These commands will deploy Cilium with its own etcd managed by etcd operator.
 
 _Note_: If you are running kubeadm in a single node please untaint it so that