Adding worker_iam_role_arn to module outputs

outputs.tf

@@ -53,3 +53,8 @@ output "worker_iam_role_name" {
   description = "IAM role name attached to EKS workers"
   value       = "${aws_iam_role.workers.name}"
 }
+
+output "worker_iam_role_arn" {
+  description = "IAM role ID attached to EKS workers"
+  value       = "${aws_iam_role.workers.arn}"
+}