Update TOX_CONSTRAINTS_FILE for stable/2023.1

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/2023.1 branch, tests will
continue to use the upper-constraints list on master.

Change-Id: I5ccdbac450a65b2addcc60a8ffc835fe8a692a8f

tox.ini

@@ -9,7 +9,7 @@ usedevelop = True
 install_command = pip install {opts} {packages}
 setenv =
    VIRTUAL_ENV={envdir}
-deps = -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+deps = -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/2023.1}
        -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
 allowlist_externals = bash
@@ -29,7 +29,7 @@ commands = /bin/bash run_tests.sh -N --integration --selenium-headless {posargs}
 commands = python setup.py testr --coverage --testr-args={posargs}
 
 [testenv:docs]
-deps = -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+deps = -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/2023.1}
        -r{toxinidir}/doc/requirements.txt
 commands =
   sphinx-build -a -E -W -b html doc/source doc/build/html