only trigger fly deploy on merge (#163)

Co-authored-by: Mailn Nifeli Snieske <malin@bekk-mac-3333.shared>

Author: malinnsnieske

.github/workflows/deploy.yml

@@ -149,6 +149,7 @@ jobs:
 
   deploy-fly:
     name: Deploy app
+    if: github.ref == 'refs/heads/main'
     runs-on: ubuntu-latest
     concurrency: deploy-group    # optional: ensure only one action runs at a time
     needs: [tests]