Update TOX_CONSTRAINTS_FILE for stable/victoria

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

Change-Id: Id057015d061f3fa14b817c32b7654ff32ba27b70

tox.ini

@@ -10,7 +10,7 @@ setenv = VIRTUAL_ENV={envdir}
          OS_STDOUT_NOCAPTURE=False
          OS_STDERR_NOCAPTURE=False
 deps =
-    -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/openstack/requirements/raw/branch/master/upper-constraints.txt}
+    -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/victoria}
     -r{toxinidir}/test-requirements.txt
     -r{toxinidir}/requirements.txt
 commands = stestr run {posargs}
@@ -67,7 +67,7 @@ application-import-names = keystoneauth1
 
 [testenv:docs]
 deps =
-    -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/openstack/requirements/raw/branch/master/upper-constraints.txt}
+    -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/victoria}
     -r{toxinidir}/doc/requirements.txt
 commands =
     bash -c "rm -rf doc/build"
@@ -87,7 +87,7 @@ commands =
 
 [testenv:releasenotes]
 deps =
-    -c{env:UPPER_CONSTRAINTS_FILE:https://opendev.org/openstack/requirements/raw/branch/master/upper-constraints.txt}
+    -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/victoria}
     -r{toxinidir}/doc/requirements.txt
 commands = sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html