Fix: [AEA-0000] - delete old stacks on merge (#167)

## Summary

- Routine Change

### Details

- delete old stacks on merge

Author: anthony-nhs

.github/workflows/delete_old_cloudformation_stacks.yml

@@ -5,6 +5,8 @@ on:
   workflow_dispatch:
   schedule:
     - cron: "0 2,14 * * *"
+  push:
+    branches: [main]
 
 # A workflow run is made up of one or more jobs that can run sequentially or in parallel
 jobs: