chore(deps): Bump vpc::terraform-aws-vpc in /tests/microsoft_ad

Bumps [vpc::terraform-aws-vpc](https://github.com/terraform-aws-modules/terraform-aws-vpc) from 5.9.0 to 5.15.0.
- [Release notes](https://github.com/terraform-aws-modules/terraform-aws-vpc/releases)
- [Changelog](https://github.com/terraform-aws-modules/terraform-aws-vpc/blob/master/CHANGELOG.md)
- [Commits](terraform-aws-modules/terraform-aws-vpc@v5.9.0...v5.15.0)

---
updated-dependencies:
- dependency-name: vpc::github::terraform-aws-modules/terraform-aws-vpc::v5.9.0
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

tests/microsoft_ad/main.tf

@@ -14,7 +14,7 @@ resource "random_string" "domain" {
 }
 
 module "vpc" {
-  source = "git::https://github.com/terraform-aws-modules/terraform-aws-vpc.git?ref=v5.9.0"
+  source = "git::https://github.com/terraform-aws-modules/terraform-aws-vpc.git?ref=v5.15.0"
 
   name            = "tardigrade-test-directory-service-${random_string.domain.result}"
   cidr            = "10.0.0.0/16"