add zvm into support matrix
add zvm into support matrix

z/VM driver is in Rocky release now and this patch adds
the z/VM support matrix update.

blueprint: add-zvm-driver-rocky

Change-Id: I58016140c7f556df91ce258733455647a26dd727

mikalstill/nova,klmitch/nova,gooddata/openstack-nova,mahak/nova,gooddata/openstack-nova,rahulunair/nova,rahulunair/nova,openstack/nova,openstack/nova,klmitch/nova,mahak/nova,mahak/nova,gooddata/openstack-nova,mikalstill/nova,klmitch/nova,openstack/nova,rahulunair/nova,klmitch/nova,gooddata/openstack-nova,mikalstill/nova