chore: build-release must close the cascading pull request (#9205)

otherwise it will linger until it is removed and will not get updated when the end-to-end tests changes. That was manually done weekly before but it is best done automatically.

## Testing

- After it is merged
- Wait 24h
- Verify the https://codeberg.org/forgejo-integration/forgejo/actions?workflow=build-release.yml passes
- Verify the corresponding pull request similar to https://code.forgejo.org/forgejo/end-to-end/pulls/922 is closed

Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/9205
Reviewed-by: Michael Kriese <michael.kriese@gmx.de>
Co-authored-by: Earl Warren <contact@earl-warren.org>
Co-committed-by: Earl Warren <contact@earl-warren.org>

.forgejo/workflows/build-release.yml

@@ -212,6 +212,7 @@ jobs:
           destination-repo: forgejo/end-to-end
           destination-branch: main
           destination-token: ${{ secrets.CASCADE_DESTINATION_TOKEN }}
+          close: true
           update: .forgejo/cascading-release-end-to-end
 
       - name: copy to experimental