Change env to staging for preview

Author: Matteo-it

.github/workflows/preview.yml

@@ -20,7 +20,7 @@ jobs:
       cancel-in-progress: false
     env:
       REPO_ACCESS_TOKEN: ${{ secrets.REPO_ACCESS_TOKEN }}
-      APP_ENV: prod
+      APP_ENV: staging
       BRANCH_NAME: ${{ github.ref_name }}
 
     steps: