Update ipv6-add-to-existing-vnet-cli.md

Updating to ULA IPv6 address space in examples

Author: ramandhillon84

articles/virtual-network/ipv6-add-to-existing-vnet-cli.md

@@ -88,13 +88,13 @@ Add IPv6 address ranges to the virtual network and subnet hosting the load balan
 az network vnet update \
 --name myVnet  \
 --resource-group MyResourceGroupSLB \
---address-prefixes  "10.0.0.0/16"  "2001:db8:deca::/48"
+--address-prefixes  "10.0.0.0/16"  "fd00:db8:deca::/48"
 
 az network vnet subnet update \
 --vnet-name myVnet \
 --name mySubnet \
 --resource-group MyResourceGroupSLB \
---address-prefixes  "10.0.0.0/24"  "2001:db8:deca:deed::/64"  
+--address-prefixes  "10.0.0.0/24"  "fd00:db8:deca:deed::/64"  
 ```
 
 ## Add IPv6 configuration to NICs