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

Updating to ULA IPv6 address space in examples

Author: ramandhillon84

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

@@ -111,7 +111,7 @@ Add IPv6 address ranges to the virtual network and subnet hosting the VMs as fol
 $vnet = Get-AzVirtualNetwork  -ResourceGroupName $rg.ResourceGroupName -Name "myVnet" 
 
 #Add IPv6 prefix to the VNET
-$vnet.addressspace.addressprefixes.add("2001:db8:deca::/48")
+$vnet.addressspace.addressprefixes.add("fd00:db8:deca::/48")
 
 #Update the running VNET
 $vnet |  Set-AzVirtualNetwork
@@ -120,7 +120,7 @@ $vnet |  Set-AzVirtualNetwork
 $subnet= $vnet.subnets[0]
 
 #Add IPv6 prefix to the Subnet (subnet of the VNET prefix, of course)
-$subnet.addressprefix.add("2001:db8:deca::/64")
+$subnet.addressprefix.add("fd00:db8:deca::/64")
 
 #Update the running VNET with the new subnet configuration
 $vnet |  Set-AzVirtualNetwork