Raise GCP network deletion timeout from 4m to 6m

* Fix a GCP errata item https://github.com/poseidon/typhoon/wiki/Errata
* Removal of a Google Cloud cluster often required 2 runs of
`terraform apply` because network resource deletes timeout
after 4m. Raise the network deletion timeout to 6m to
ensure apply only needs to be run once to remove a cluster

CHANGES.md

@@ -10,6 +10,7 @@ Notable changes between versions.
 
 * Allow controller nodes to span more than 3 zones if available in a region ([#504](https://github.com/poseidon/typhoon/pull/504))
 * Eliminate extraneous controller instance groups in single-controller clusters ([#504](https://github.com/poseidon/typhoon/pull/504))
+* Raise network deletion timeout from 4m to 6m ([#505](https://github.com/poseidon/typhoon/pull/505))
 
 #### Addons
 

google-cloud/container-linux/kubernetes/network.tf

@@ -2,6 +2,10 @@ resource "google_compute_network" "network" {
   name                    = var.cluster_name
   description             = "Network for the ${var.cluster_name} cluster"
   auto_create_subnetworks = true
+
+  timeouts {
+    delete = "6m"
+  }
 }
 
 resource "google_compute_firewall" "allow-ssh" {