make project creation optional in gcs to bq example

examples/data-solutions/gcs-to-bq-with-dataflow/main.tf

@@ -29,6 +29,7 @@ module "project-service" {
   name            = var.project_service_name
   parent          = var.root_node
   billing_account = var.billing_account
+  project_create  = var.project_create
   services = [
     "bigquery.googleapis.com",
     "bigqueryreservation.googleapis.com",
@@ -47,6 +48,7 @@ module "project-kms" {
   name            = var.project_kms_name
   parent          = var.root_node
   billing_account = var.billing_account
+  project_create  = var.project_create
   services = [
     "cloudkms.googleapis.com",
   ]

examples/data-solutions/gcs-to-bq-with-dataflow/variables.tf

@@ -16,6 +16,7 @@
 variable "billing_account" {
   description = "Billing account id used as default for new projects."
   type        = string
+  default     = null
 }
 
 variable "location" {
@@ -24,6 +25,12 @@ variable "location" {
   default     = "europe"
 }
 
+variable "project_create" {
+  description = "Set to true to create projects, will use existing ones by default."
+  type        = bool
+  default     = false
+}
+
 variable "project_kms_name" {
   description = "Name for the new KMS Project."
   type        = string
@@ -43,6 +50,7 @@ variable "region" {
 variable "root_node" {
   description = "The resource name of the parent Folder or Organization. Must be of the form folders/folder_id or organizations/org_id."
   type        = string
+  default     = null
 }
 
 variable "ssh_source_ranges" {