Add OpenStack as supported for IPv6 clusters

Author: MaysaMacedo

modules/nw-ovn-kubernetes-matrix.adoc

@@ -64,7 +64,7 @@ endif::[]
 
 2. Egress router for OVN-Kubernetes supports only redirect mode.
 
-3. IPv6 is supported only on bare metal, vSphere, {ibm-power-name}, and {ibm-z-name} clusters.
+3. IPv6 is supported only on bare metal, vSphere, {ibm-power-name}, {ibm-z-name}, and Red Hat OpenStack clusters.
 
-4. IPv6 single stack is not supported on {ibm-power-name} and {ibm-z-name} clusters.
+4. IPv6 single stack is not supported on {ibm-power-name}, {ibm-z-name}, and Red Hat OpenStack clusters.
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