[CI][9-stream][stable only] Use last python3.9 supported tempest tag

tempest master dropped the python3.9 support in [1], so
we need to use tempest 45.0.0 which last version supporting
python3.9.

[1] https://review.opendev.org/c/openstack/tempest/+/966101

Related-Bug: #2130551
Signed-off-by: Yatin Karel <ykarel@redhat.com>
Change-Id: Ia0bbb62119621d2cb5781a6e12bf1f2afab1d72e
(cherry picked from commit d796ecd5fe)

zuul.d/tempest-singlenode.yaml

@@ -779,6 +779,7 @@
         br-ex-tcpdump: true
         br-int-flows: true
       devstack_localrc:
+        TEMPEST_BRANCH: 45.0.0
         TEMPEST_VENV_UPPER_CONSTRAINTS: '/opt/stack/requirements/upper-constraints.txt'
       devstack_local_conf:
         test-config:
@@ -797,6 +798,7 @@
       nslookup_target: 'opendev.org'
       configure_swap_size: 4096
       devstack_localrc:
+        TEMPEST_BRANCH: 45.0.0
         TEMPEST_VENV_UPPER_CONSTRAINTS: '/opt/stack/requirements/upper-constraints.txt'
       devstack_local_conf:
         test-config: