Add cluster CA certificate as output for gke-cluster

modules/gke-cluster/README.md

@@ -70,6 +70,7 @@ module "cluster-1" {
 
 | name | description | sensitive |
 |---|---|:---:|
+| ca_certificate | Public certificate of the cluster (base64-encoded). | ✓ |
 | cluster | Cluster resource. | ✓ |
 | endpoint | Cluster endpoint. |  |
 | location | Cluster location. |  |

modules/gke-cluster/outputs.tf

@@ -39,3 +39,9 @@ output "name" {
   description = "Cluster name."
   value       = google_container_cluster.cluster.name
 }
+
+output "ca_certificate" {
+  description = "Public certificate of the cluster (base64-encoded)."
+  value       = google_container_cluster.cluster.master_auth.0.cluster_ca_certificate
+  sensitive   = true
+}