Make terraform respect "generate_name" kubernetes_*

generate_name.tf

provider "kubernetes" {
  config_context = "docker-desktop"
}

resource "kubernetes_job" "demo" {
  metadata {
    generate_name = "demo-"
  }
  spec {
    template {
      metadata {
      }
      spec {
        container {
          name    = "pi"
          image   = "perl"
          command = ["perl", "-Mbignum=bpi", "-wle", "print bpi(100)"]
          env {
            name  = "_DO_REGENERATE"
            value = "${timestamp()}"
          }

        }
        restart_policy = "Never"
      }
    }
    backoff_limit = 4
  }
}