add academy_data_source_arn to stg vars (#2239)

Author: timburke-hackit

terraform/config/stg.tfvars

@@ -18,4 +18,5 @@ redshift_port                       = 5440
 emails_to_notify_with_budget_alerts = ["saml-aws-data-platform-admins@hackney.gov.uk"]
 datahub_url                         = "https://datahub-pre-prod.hackney.gov.uk"
 rentsense_target_path               = "hackneylondonborough.beta/rent/"
-rentsense_ft_target_path            = "hackneylondonborough.beta/fta/"
+rentsense_ft_target_path            = "hackneylondonborough.beta/fta/"
+academy_data_source_arn             = "arn:aws:iam::704265464895:role/academy-app-prod"