Update generation-2.md

Author: cynthn

articles/virtual-machines/windows/generation-2.md

@@ -56,7 +56,9 @@ Generation 2 VMs support the following Marketplace images:
 * Windows Server 2012 Datacenter
 * SUSE Linux Enterprise Server 15 SP1
 * SUSE Linux Enterprise Server 12 SP4
-* Ubuntu Server 16.04+
+* Ubuntu Server 16.04,18.04, 19.04, 19.10
+* RHEL 8.0
+
 
 ## On-premises vs. Azure generation 2 VMs