change output syntax

Author: Nikita Dugar

outputs.tf

@@ -2,16 +2,12 @@
 #Description : Terraform sftp module variables.
 
 output "id" {
-  value = concat(
-    aws_transfer_server.transfer_server.*.id
-  )[0]
+  value = join("", aws_transfer_server.transfer_server.*.id)
   description = "The Server ID of the Transfer Server (e.g. s-12345678)."
 }
 
 output "transfer_server_endpoint" {
-  value = concat(
-    aws_transfer_server.transfer_server.*.endpoint
-  )[0]
+  value = join("", aws_transfer_server.transfer_server.*.endpoint)
   description = "The endpoint of the Transfer Server (e.g. s-12345678.server.transfer.REGION.amazonaws.com)."
 }