Update workflow

Author: ChrSchu90

.github/workflows/update-upstream-deps.yml

@@ -54,7 +54,7 @@ jobs:
       id: app-token
       uses: actions/create-github-app-token@v2
       with:
-        app-id: ${{ vars.UPDATE_BOT_APP_ID }}
+        app-id: ${{ secrets.UPDATE_BOT_APP_ID }}
         private-key: ${{ secrets.UPDATE_BOT_PRIVATE_KEY }}
 
     - name: Create Pull Request