Dualstack support (cloudposse#247)

Author: ngoyal16

README.md

@@ -259,6 +259,7 @@ Available targets:
 | <a name="input_multi_az_enabled"></a> [multi\_az\_enabled](#input\_multi\_az\_enabled) | Multi AZ (Automatic Failover must also be enabled.  If Cluster Mode is enabled, Multi AZ is on by default, and this setting is ignored) | `bool` | `false` | no |
 | <a name="input_name"></a> [name](#input\_name) | ID element. Usually the component or solution name, e.g. 'app' or 'jenkins'.<br/>This is the only ID element not also included as a `tag`.<br/>The "name" tag is set to the full `id` string. There is no tag with the value of the `name` input. | `string` | `null` | no |
 | <a name="input_namespace"></a> [namespace](#input\_namespace) | ID element. Usually an abbreviation of your organization name, e.g. 'eg' or 'cp', to help ensure generated IDs are globally unique | `string` | `null` | no |
+| <a name="input_network_type"></a> [network\_type](#input\_network\_type) | The network type of the cluster. Valid values: ipv4, ipv6, dual\_stack. | `string` | `"ipv4"` | no |
 | <a name="input_notification_topic_arn"></a> [notification\_topic\_arn](#input\_notification\_topic\_arn) | Notification topic arn | `string` | `""` | no |
 | <a name="input_ok_actions"></a> [ok\_actions](#input\_ok\_actions) | The list of actions to execute when this alarm transitions into an OK state from any other state. Each action is specified as an Amazon Resource Number (ARN) | `list(string)` | `[]` | no |
 | <a name="input_parameter"></a> [parameter](#input\_parameter) | A list of Redis parameters to apply. Note that parameters may differ from one Redis family to another | <pre>list(object({<br/>    name  = string<br/>    value = string<br/>  }))</pre> | `[]` | no |