docs: Correct example typo for NTP address (#2154)

examples/eks_managed_node_group/main.tf

@@ -92,7 +92,7 @@ module "eks" {
   }
 
   # Extend node-to-node security group rules
-  node_security_group_ntp_ipv4_cidr_block = ["fd00:ec2::123/128"]
+  node_security_group_ntp_ipv6_cidr_block = ["fd00:ec2::123/128"]
   node_security_group_additional_rules = {
     ingress_self_all = {
       description = "Node to node all ports/protocols"