fix: correct syntax for network block in hcloud_server resource

terraform/hetzner_ftp_server.tf

@@ -6,9 +6,9 @@ resource "hcloud_server" "ftp-server" {
     ipv4_enabled = true
     ipv6_enabled = true
   }
-  network [
+  network {
     network_id = resource.hcloud_network.production_network.id
-  ]
+  }
   firewall_ids    = [hcloud_firewall.production_fw.id]
 }