Pin EKS module to ~> 21.23.0 to avoid breaking v21.24.0

v21.24.0 (released 2026-06-24) raised its required AWS provider floor
to >= 6.52, conflicting with this repo's pin of <= 6.46.0 and breaking
terraform init --upgrade in the cluster stack. Pinning to the 21.23.x
band keeps the provider floor at >= 6.42 (compatible with <= 6.46.0).

Author: shapirov103

platform/infra/terraform/cluster/main.tf

@@ -3,7 +3,7 @@ module "eks" {
   #checkov:skip=CKV_TF_2:We are using version control for those modules
   for_each = var.clusters
   source  = "terraform-aws-modules/eks/aws"
-  version = "~> 21.15"
+  version = "~> 21.23.0"
 
   name                   = each.value.name
   kubernetes_version     = each.value.kubernetes_version