add new option variables

mongodb/variables.tf

@@ -30,7 +30,9 @@ variable "mongodb_instance_flavor" {
 variable "mongodb_instance_options" {
   description = "options for mongodb"
   type = object({
-    type = string
+    type                       = string
+    snapshot_retention_days    = number
+    point_in_time_window_hours = number
   })
 }