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: I355053e7ed0298d630cd2cdb3b4ebeaa28f5ad80

tox.ini

@@ -12,7 +12,7 @@ setenv = VIRTUAL_ENV={envdir}
 
 usedevelop = True
 install_command = pip install \
-                  -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master} \
+                  -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/2023.1} \
                   -U {opts} {packages}
 deps = -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
@@ -26,7 +26,7 @@ allowlist_externals = find
 
 [testenv:pep8]
 deps =
-  -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+  -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/2023.1}
   -r{toxinidir}/test-requirements.txt
 commands =
     flake8
@@ -85,7 +85,7 @@ commands =
 
 [testenv:releasenotes]
 deps =
-    -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+    -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/2023.1}
     -r{toxinidir}/doc/requirements.txt
 allowlist_externals = rm
 commands =