Update virtual-nodes-cli.md

Author: CocoWang-wql

articles/aks/virtual-nodes-cli.md

@@ -265,7 +265,7 @@ az network profile delete --id $NETWORK_PROFILE_ID -y
 SAL_ID=$(az network vnet subnet show --resource-group $RES_GROUP --vnet-name $AKS_VNET --name $AKS_SUBNET --query id --output tsv)/providers/Microsoft.ContainerInstance/serviceAssociationLinks/default
 
 # Delete the service association link for the subnet
-az resource delete --ids $SAL_ID --api-version {api-version}
+az resource delete --ids $SAL_ID --api-version 2021-10-01
 
 # Delete the subnet delegation to Azure Container Instances
 az network vnet subnet update --resource-group $RES_GROUP --vnet-name $AKS_VNET --name $AKS_SUBNET --remove delegations