chore(deps): update terraform-aws-modules/rds/aws requirement from ~> 6.12.0 to ~> 6.13.0

Updates the requirements on [terraform-aws-modules/rds/aws](https://github.com/terraform-aws-modules/terraform-aws-rds) to permit the latest version.
- [Release notes](https://github.com/terraform-aws-modules/terraform-aws-rds/releases)
- [Changelog](https://github.com/terraform-aws-modules/terraform-aws-rds/blob/master/CHANGELOG.md)
- [Commits](terraform-aws-modules/terraform-aws-rds@v6.12.0...v6.13.0)

---
updated-dependencies:
- dependency-name: terraform-aws-modules/rds/aws
  dependency-version: 6.13.0
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

main.tf

@@ -44,7 +44,7 @@ module "postgres_security_group" {
 
 module "kong_rds" {
   source  = "terraform-aws-modules/rds/aws"
-  version = "~> 6.12.0"
+  version = "~> 6.13.0"
 
   identifier           = local.rds.db_identifier
   engine               = local.rds.engine