updated the examples with project_id

Author: Daisyprakash

examples/gke_standard_cluster/main.tf

@@ -87,7 +87,7 @@ module "node_pool" {
   source  = "terraform-google-modules/kubernetes-engine/google//modules/gke-node-pool"
   version = "~> 38.0"
 
-  project  = var.project_id
+  project_id  = var.project_id
   location = var.region
   cluster  = module.gke.cluster_name
   node_config = {