Update TOX_CONSTRAINTS_FILE for stable/2023.2

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/2023.2 branch, tests will
continue to use the upper-constraints list on master.

Change-Id: Ib13318d81e1790a26dc7f035bf1d2e9f6fa91de7

tox.ini

@@ -11,7 +11,7 @@ setenv =
 # TODO(stephenfin): Remove once we bump our upper-constraint to SQLAlchemy 2.0
   SQLALCHEMY_WARN_20=1
 deps =
-  -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+  -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/2023.2}
   -r{toxinidir}/test-requirements.txt
   .[ldap,memcache,mongodb]
 commands =
@@ -43,7 +43,7 @@ passenv = FAST8_NUM_COMMITS
 # NOTE(browne): This is required for the integration test job of the bandit
 # project. Please do not remove.
 deps =
-  -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+  -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/2023.2}
   -r{toxinidir}/requirements.txt
   .[bandit]
 commands = bandit -r keystone -x 'keystone/tests/*'
@@ -74,7 +74,7 @@ passenv = KSTEST_*
 
 [testenv:functional]
 deps =
-  -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
+  -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/2023.2}
   -r{toxinidir}/test-requirements.txt
 setenv = OS_TEST_PATH=./keystone/tests/functional
 commands =
@@ -112,7 +112,7 @@ per-file-ignores =
 
 [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/2023.2}
   -r{toxinidir}/doc/requirements.txt
   .[ldap,memcache,mongodb]
 commands=