So that it does not use docker.io
The test happens at `.forgejo/workflows/build-release-integration.yml`
Reviewed-on: https://codeberg.org/forgejo/forgejo/pulls/6573
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>