adding 4x master node sizes

Author: Kevin Lamenzo

articles/openshift/support-policies-v4.md

@@ -61,3 +61,11 @@ Azure Red Hat OpenShift 4 supports worker node instances on the following virtua
 |Fsv2|Standard_F8s_v2|8|16|
 |Fsv2|Standard_F16s_v2|16|32|
 |Fsv2|Standard_F32s_v2|32|64|
+
+### Master nodes
+
+|Series|Size|vCPU|Memory: GiB|
+|-|-|-|-|
+|Dsv3|Standard_D8s_v3|8|32|
+|Dsv3|Standard_D16s_v3|16|64|
+|Dsv3|Standard_D32s_v3|32|128|