Fix docker_gwbridge network overlaping

This patch changes the docker_gwbridge (10.20.30.0/16) which overlaps with
heat_net(10.20.0.0/24) to 10.21.30.0/16

Change-Id: I50b3d9ea3d06569eea78dd39d463f7afb8f32f36
Related-Prod: PROD-27025
diff --git a/classes/cluster/virtual-mcp11-aio-advanced-keystone/infra/config.yml b/classes/cluster/virtual-mcp11-aio-advanced-keystone/infra/config.yml
index 1cbf4a7..a8295c7 100644
--- a/classes/cluster/virtual-mcp11-aio-advanced-keystone/infra/config.yml
+++ b/classes/cluster/virtual-mcp11-aio-advanced-keystone/infra/config.yml
@@ -15,6 +15,7 @@
     openldap_admin_password: workshop
     openldap_config_password: workshop
     openldap_readonly_password: workshop
+    docker_gwbridge_subnet: 10.21.0.0/16
   docker:
     host:
       insecure_registries: