Updated README with latest CNI plugin version

Signed-off-by: Roberto Bonafiglia <roberto.bonafiglia@suse.com>

README.md

@@ -59,9 +59,15 @@ In case a firewall is configured ensure to enable the right port used by the con
 Flannel uses `portmap` as CNI network plugin by default; when deploying Flannel ensure that the [CNI Network plugins][Network-plugins] are installed in `/opt/cni/bin` the latest binaries can be downloaded with the following commands:
 
 ```bash
+ARCH=$(uname -m)
+  case $ARCH in
+    armv7*) ARCH="arm";;
+    aarch64) ARCH="arm64";;
+    x86_64) ARCH="amd64";;
+  esac
 mkdir -p /opt/cni/bin
-curl -O -L /~https://github.com/containernetworking/plugins/releases/download/v1.2.0/cni-plugins-linux-amd64-v1.2.0.tgz
-tar -C /opt/cni/bin -xzf cni-plugins-linux-amd64-v1.2.0.tgz
+curl -O -L /~https://github.com/containernetworking/plugins/releases/download/v1.5.1/cni-plugins-linux-$ARCH-v1.5.1.tgz
+tar -C /opt/cni/bin -xzf cni-plugins-linux-$ARCH-v1.5.1.tgz
 ```
 
 ## Getting started on Docker