docs: update variable engine description

Author: Knapsack44

README.md

@@ -326,7 +326,7 @@ No modules.
 | <a name="input_enable_local_write_forwarding"></a> [enable\_local\_write\_forwarding](#input\_enable\_local\_write\_forwarding) | Whether read replicas can forward write operations to the writer DB instance in the DB cluster. By default, write operations aren't allowed on reader DB instances. | `bool` | `null` | no |
 | <a name="input_enabled_cloudwatch_logs_exports"></a> [enabled\_cloudwatch\_logs\_exports](#input\_enabled\_cloudwatch\_logs\_exports) | Set of log types to export to cloudwatch. If omitted, no logs will be exported. The following log types are supported: `audit`, `error`, `general`, `slowquery`, `postgresql` | `list(string)` | `[]` | no |
 | <a name="input_endpoints"></a> [endpoints](#input\_endpoints) | Map of additional cluster endpoints and their attributes to be created | `any` | `{}` | no |
-| <a name="input_engine"></a> [engine](#input\_engine) | The name of the database engine to be used for this DB cluster. Defaults to `aurora`. Valid Values: `aurora`, `aurora-mysql`, `aurora-postgresql` | `string` | `null` | no |
+| <a name="input_engine"></a> [engine](#input\_engine) | The name of the database engine to be used for this DB cluster. Defaults to `aurora`. Valid Values: `aurora`, `aurora-mysql`, `aurora-postgresql`, `mysql`, `postgres` | `string` | `null` | no |
 | <a name="input_engine_lifecycle_support"></a> [engine\_lifecycle\_support](#input\_engine\_lifecycle\_support) | The life cycle type for this DB instance. This setting is valid for cluster types Aurora DB clusters and Multi-AZ DB clusters. Valid values are `open-source-rds-extended-support`, `open-source-rds-extended-support-disabled`. Default value is `open-source-rds-extended-support`. | `string` | `null` | no |
 | <a name="input_engine_mode"></a> [engine\_mode](#input\_engine\_mode) | The database engine mode. Valid values: `global`, `multimaster`, `parallelquery`, `provisioned`, `serverless`. Defaults to: `provisioned` | `string` | `"provisioned"` | no |
 | <a name="input_engine_native_audit_fields_included"></a> [engine\_native\_audit\_fields\_included](#input\_engine\_native\_audit\_fields\_included) | Specifies whether the database activity stream includes engine-native audit fields. This option only applies to an Oracle DB instance. By default, no engine-native audit fields are included | `bool` | `false` | no |

variables.tf

@@ -181,7 +181,7 @@ variable "enable_http_endpoint" {
 }
 
 variable "engine" {
-  description = "The name of the database engine to be used for this DB cluster. Defaults to `aurora`. Valid Values: `aurora`, `aurora-mysql`, `aurora-postgresql`"
+  description = "The name of the database engine to be used for this DB cluster. Defaults to `aurora`. Valid Values: `aurora`, `aurora-mysql`, `aurora-postgresql`, `mysql`, `postgres`"
   type        = string
   default     = null
 }