0.19.0 Add `eks_cluster_managed_security_group_id` output

what

• Add eks_cluster_managed_security_group_id output

why

• EKS managed Node Groups do not expose nor accept any Security Groups
• Instead, EKS creates a Security Group and applies it to ENI that is attached to EKS Control Plane master nodes and to any managed workloads
• Since that Security Group is applied to the EKS worker nodes, it can be used as a source Security Group for other resources, e.g. EFS or RDS to allow ingress traffic to the resources