Add destroy time flag (#580)

* Add destroy-time flag

* Update changelog

Fix cluster count

* Fix cluster count

* Fix docs

* Fix outputs

* Fix unsupported attribute on cluster_certificate_authority_data output

Co-Authored-By: Daniel Piddock <33028589+dpiddockcmp@users.noreply.github.com>

* Remove unnecessary flatten from cluster_endpoint output

Co-Authored-By: Daniel Piddock <33028589+dpiddockcmp@users.noreply.github.com>

* Improve description of var.enabled

* Fix errors manifesting when used on an existing-cluster

* Update README.md

* Renamed destroy-time flag

* Revert removal of changelog addition entry

* Update flag name in readme

* Update flag variable name

* Update cluster referencing for consistency

* Update flag name to `create_eks`

* Fixed incorrect count-based reference to aws_eks_cluster.this (there's only one)

* Replaced all incorrect aws_eks_cluster.this[count.index] references (there will be just one, so using '[0]').

* Changelog update, explicitly mentioning flag

* Fixed interpolation deprecation warning

* Fixed outputs to support conditional cluster

* Applied create_eks to aws_auth.tf

* Removed unused variable. Updated Changelog. Formatting.

* Fixed references to aws_eks_cluster.this[0] that would raise errors when setting create_eks to false whilst having launch templates or launch configurations configured.

* Readme and example updates.

* Revert "Readme and example updates."

This reverts commit 18a0746355.

* Updated readme section of conditionally creation with provider example.

* Added conditions to node_groups.

* Fixed reversed map_roles check

* Update aws_auth.tf

Revert this due to https://github.com/terraform-aws-modules/terraform-aws-eks/pull/611

outputs.tf

@@ -1,26 +1,26 @@
 output "cluster_id" {
   description = "The name/id of the EKS cluster."
-  value       = aws_eks_cluster.this.id
+  value       = element(concat(aws_eks_cluster.this.*.id, list("")), 0)
 }
 
 output "cluster_arn" {
   description = "The Amazon Resource Name (ARN) of the cluster."
-  value       = aws_eks_cluster.this.arn
+  value       = element(concat(aws_eks_cluster.this.*.arn, list("")), 0)
 }
 
 output "cluster_certificate_authority_data" {
   description = "Nested attribute containing certificate-authority-data for your cluster. This is the base64 encoded certificate data required to communicate with your cluster."
-  value       = aws_eks_cluster.this.certificate_authority[0].data
+  value       = element(concat(aws_eks_cluster.this[*].certificate_authority[0].data, list("")), 0)
 }
 
 output "cluster_endpoint" {
   description = "The endpoint for your EKS Kubernetes API."
-  value       = aws_eks_cluster.this.endpoint
+  value       = element(concat(aws_eks_cluster.this.*.endpoint, list("")), 0)
 }
 
 output "cluster_version" {
   description = "The Kubernetes server version for the EKS cluster."
-  value       = aws_eks_cluster.this.version
+  value       = element(concat(aws_eks_cluster.this[*].version, list("")), 0)
 }
 
 output "cluster_security_group_id" {
@@ -45,17 +45,17 @@ output "cluster_iam_role_arn" {
 
 output "cluster_oidc_issuer_url" {
   description = "The URL on the EKS cluster OIDC Issuer"
-  value       = concat(aws_eks_cluster.this.identity.*.oidc.0.issuer, [""])[0]
+  value       = concat(aws_eks_cluster.this[*].identity[*].oidc.0.issuer, [""])[0]
 }
 
 output "cloudwatch_log_group_name" {
   description = "Name of cloudwatch log group created"
-  value       = aws_cloudwatch_log_group.this.*.name
+  value       = aws_cloudwatch_log_group.this[*].name
 }
 
 output "kubeconfig" {
   description = "kubectl config file contents for this EKS cluster."
-  value       = data.template_file.kubeconfig.rendered
+  value       = concat(data.template_file.kubeconfig[*].rendered, [""])[0]
 }
 
 output "kubeconfig_filename" {