Update Container Linux kubeadm install instructions for crictl (#9798)

* Update Container Linux kubeadm install instructions for crictl

* fixed crictl install instructions

content/en/docs/setup/independent/install-kubeadm.md

@@ -21,7 +21,7 @@ see the [Using kubeadm to Create a Cluster](/docs/setup/independent/create-clust
   - RHEL 7
   - Fedora 25/26 (best-effort)
   - HypriotOS v1.0.1+
-  - Container Linux (tested with 1576.4.0)
+  - Container Linux (tested with 1800.6.0)
 * 2 GB or more of RAM per machine (any less will leave little room for your apps)
 * 2 CPUs or more 
 * Full network connectivity between all machines in the cluster (public or private network is fine)
@@ -213,6 +213,14 @@ mkdir -p /opt/cni/bin
 curl -L "https://github.com/containernetworking/plugins/releases/download/${CNI_VERSION}/cni-plugins-amd64-${CNI_VERSION}.tgz" | tar -C /opt/cni/bin -xz
 ```
 
+Install crictl (required for kubeadm / Kubelet Container Runtime Interface (CRI))
+
+```bash
+CRICTL_VERSION="v1.11.1"
+mkdir -p /opt/bin
+curl -L "https://github.com/kubernetes-incubator/cri-tools/releases/download/${CRICTL_VERSION}/crictl-${CRICTL_VERSION}-linux-amd64.tar.gz" | tar -C /opt/bin -xz
+```
+
 Install `kubeadm`, `kubelet`, `kubectl` and add a `kubelet` systemd service:
 
 ```bash