BZ2024738-Added Azure Stack Hub as supported platform for UPI install

Author: mjpytlak

modules/supported-platforms-for-openshift-clusters.adoc

@@ -32,6 +32,7 @@ In {product-title} {product-version}, you can install a cluster that uses user-p
 
 * AWS
 * Azure
+* Azure Stack Hub
 * GCP
 * {rh-openstack}
 * {rh-virtualization}