fix: update landing zone version used in catalog validation to pull in fix for cluster issue (#279)

Author: ocofaigh

tests/resources/main.tf

@@ -15,7 +15,7 @@ module "resource_group" {
 ##############################################################################
 
 module "landing_zone" {
-  source                              = "git::https://github.com/terraform-ibm-modules/terraform-ibm-landing-zone//patterns//roks//module?ref=v7.0.2"
+  source                              = "git::https://github.com/terraform-ibm-modules/terraform-ibm-landing-zone//patterns//roks//module?ref=v7.3.0"
   region                              = var.region
   prefix                              = var.prefix
   tags                                = var.resource_tags