Continuous updates always outputs to stderr

[xinyuluo]

I tried to set up a systemd service to continuously update data based on https://nominatim.org/release-docs/latest/admin/Update/#continuous-updates. In my service description I have:

StandardOutput=append:/var/log/nominatim-updates.log
StandardError=append:/var/log/nominatim-updates.error.log

The tool itself works well, but it seems like all the logs are outputted to stderr (i.e. /var/log/nominatim-updates.log has empty contents).