Add an output for the generated service account.

terraform/modules/workload_identity_account/workload_identity_account.tf

@@ -18,6 +18,11 @@ variable "k8s_service_account" {
   type        = string
 }
 
+output "service_account" {
+  description = "The google_service_account that has been bound to the kubernetes service account."
+  value       = google_service_account.service_account
+}
+
 resource "google_service_account" "service_account" {
   account_id   = "wi-${var.k8s_namespace}-${var.k8s_service_account}"
   display_name = "Workload identity account for GKE [${var.k8s_namespace}/${var.k8s_service_account}]"