Update TOX_CONSTRAINTS_FILE for stable/2025.2

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/2025.2 branch, tests will
continue to use the upper-constraints list on master.

Change-Id: Ifeebc9bea14abf25776e53da4828d86bf41db962
Signed-off-by: OpenStack Release Bot <infra-root@openstack.org>
Generated-By: openstack/project-config:roles/copy-release-tools-scripts/files/release-tools/functions

tox.ini

@@ -19,7 +19,7 @@ passenv =
   no_proxy
   NO_PROXY
 deps =
-    -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+    -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/2025.2}
     -r{toxinidir}/requirements.txt
     -r{toxinidir}/test-requirements.txt
 commands =
@@ -56,7 +56,7 @@ commands = {posargs}
 
 [testenv:docs]
 deps =
-    -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+    -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/2025.2}
     -r{toxinidir}/doc/requirements.txt
 commands =
     rm -rf doc/html doc/build
@@ -73,7 +73,7 @@ exclude=.venv,.git,.tox,dist,doc,*lib/python*,*egg,tools
 
 [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/2025.2}
     -r{toxinidir}/doc/requirements.txt
 commands =
   rm -rf releasenotes/build