Fix download_artifact_job for  promote-openstack-manuals-developer
Fix download_artifact_job for  promote-openstack-manuals-developer

This was missed in a recent change, fix the name to match what is run.

See https://review.opendev.org/676967 for a failure and job names.

Change-Id: I8e9b28e161fde4de9762fc6d2d40ec01d645e697

openstack-infra/project-config,openstack-infra/project-config