Add output for transit encryption mode in outputs.tf (#266)

Author: milldr

outputs.tf

@@ -57,4 +57,9 @@ output "cluster_enabled" {
 output "serverless_enabled" {
   value       = var.serverless_enabled
   description = "Indicates if serverless mode is enabled"
-}
+}
+
+output "transit_encryption_mode" {
+  value       = join("", aws_elasticache_replication_group.default[*].transit_encryption_mode)
+  description = "The transit encryption mode of the replication group"
+}