specify default release tag (#52)

* specify default release tag

* update changeset

.changeset/odd-mugs-speak.md

@@ -0,0 +1,7 @@
+---
+"@common-fate/terraform-aws-common-fate-deployment": minor
+---
+
+A default application release tag is now specified as part of the Terraform module. If you've been using the `release_tag` parameter, you should now remove this parameter from the stack to use the application versions bundled with the Terraform module.
+
+The initial bundled application release is v1.3.1.

variables.tf

@@ -16,8 +16,9 @@ variable "aws_region" {
 }
 
 variable "release_tag" {
-  description = "Specifies the tag for frontend and backend images, e.g v1.2.0"
+  description = "Override the application release tag to be used in the deployment. As of module version v1.13.0, application versions are bundled into the Terraform module, and so in most cases you should not override this."
   type        = string
+  default     = "v1.3.1"
 }
 
 variable "app_certificate_arn" {