doc/designs: add Random Serial Numbers v3 support
Related: https://pagure.io/freeipa/issue/2016
Signed-off-by: Rob Crittenden <rcritten@redhat.com>
Reviewed-By: Florence Blanc-Renaud <flo@redhat.com>
Reviewed-By: Francisco Trivino <ftrivino@redhat.com>
Reviewed-By: Alexander Bokovoy <abokovoy@redhat.com>