Start a module for creating a workload identity service account.

terraform/modules/workload_identity_account/workload_identity_account.tf

@@ -0,0 +1,8 @@
+# Requires a google_iam_workload_identity_pool to exist, but it is not
+# referenced in this module.
+
+
+variable "project" {
+  description = "Project ID."
+  type        = string
+}