Wire up the tripleo-upgrades-wallaby-pipeline

This wires up the wallaby upgrades jobs added in tripleo-ci depends-on.
See topic branch [1] for related patches. The parent patch at [2] is
needed to fix a bug with the undercloud upgrade.

[1] https://review.opendev.org/q/topic:wallaby-upgrade-jobs
[2] https://review.opendev.org/c/openstack/tripleo-heat-templates/+/800007

Depends-On: https://review.opendev.org/c/openstack/tripleo-ci/+/793120
Change-Id: Ifd237a22f0d80a450eb0f95c1cb5be276858387f

zuul.d/layout.yaml

@@ -7,7 +7,7 @@
       - tripleo-standalone-scenarios-pipeline
       - openstack-python3-wallaby-jobs
       - tripleo-standalone-multinode-ipa-pipeline
-      - tripleo-upgrades-master-pipeline
+      - tripleo-upgrades-wallaby-pipeline
     check:
       jobs:
         - openstack-tox-pep8