Add data.tf to iam directory in refactoring guide (#4888)

Missing file in iam folder.

Author: vit100-trader

docs-starlight/src/content/docs/02-guides/01-terralith-to-terragrunt/05-step-2-refactoring.mdx

@@ -613,6 +613,7 @@ You should have a filesystem layout that look like the following for your IaC no
       - vars-required.tf
       - versions.tf
     - iam
+      - data.tf
       - main.tf
       - outputs.tf
       - vars-required.tf