Update variables files

variables.tf

@@ -20,7 +20,7 @@ variable "snapshot_identifier" {
 
 variable "db_allocated_storage" {
   description = "The allocated storage in gibibytes"
-  default     = "20" # 20 GiB is minimum storage size for RDS PostgreSQL gp3 storage type.
+  default     = "20" # Minimum 'gp3' storage size is 20 GiB for Amazon RDS.
   type        = number
 }