docs: Change instance type from t2 to t3 in examples (#1169)

examples/managed_node_groups/main.tf

@@ -122,7 +122,7 @@ module "eks" {
   # worker_groups_launch_template = [
   #   {
   #     name                 = "worker-group-1"
-  #     instance_type        = "t2.small"
+  #     instance_type        = "t3.small"
   #     asg_desired_capacity = 2
   #     public_ip            = true
   #   }