[chores] Fixed QA

Author: atif09

.github/workflows/backport.yml

@@ -40,4 +40,4 @@ jobs:
       comment_body: ${{ github.event.comment.body }}
     secrets:
       app_id: ${{ secrets.OPENWISP_BOT_APP_ID }}
-      private_key: ${{ secrets.OPENWISP_BOT_PRIVATE_KEY }}
+      private_key: ${{ secrets.OPENWISP_BOT_PRIVATE_KEY }}