Update the URL to the upper-constraints file to point to the redirect
rule on releases.openstack.org so that anyone working on this branch
will switch to the correct upper-constraints list automatically when
the requirements repository branches.
Until the requirements repository has as stable/2024.1 branch, tests will
continue to use the upper-constraints list on master.
Change-Id: I85ed3a39421a298e7dc08d88f047e537af0f0b78