Update 'Maintained' stable branch jobs on master gate

We have stable/yoga released and stable/ussuri is in
'Extended Maintenance' state. Current 'Maintained'
stable branches are yoga, xena, wallaby, and victoria.

As per tempest stable branch testing policy[1], adding the
newly released stable/yoga job and remove the EM stable/ussuri
job.

[1] https://docs.openstack.org/tempest/latest/stable_branch_testing_policy.html

Change-Id: Ie0a39407a98875afc7d2d87663b4a17c27fa8fc7

.zuul.yaml

@@ -10,10 +10,10 @@
         - monasca-tempest-python3-cassandra
         - monasca-tempest-log-python3-influxdb
         - build-monasca-docker-image
+        - monasca-tempest-influxdb-yoga
         - monasca-tempest-influxdb-xena
         - monasca-tempest-influxdb-wallaby
         - monasca-tempest-influxdb-victoria
-        - monasca-tempest-influxdb-ussuri
     gate:
       queue: monasca
       jobs:
@@ -29,6 +29,11 @@
       jobs:
         - publish-monasca-tempest-plugin-docker-image
 
+- job:
+    name: monasca-tempest-influxdb-yoga
+    parent: monasca-tempest-python3-influxdb
+    override-checkout: stable/yoga
+
 - job:
     name: monasca-tempest-influxdb-xena
     parent: monasca-tempest-python3-influxdb
@@ -44,12 +49,6 @@
     parent: monasca-tempest-python3-influxdb
     override-checkout: stable/victoria
 
-- job:
-    name: monasca-tempest-influxdb-ussuri
-    parent: monasca-tempest-python3-influxdb
-    nodeset: openstack-single-node-bionic
-    override-checkout: stable/ussuri
-
 - job:
     name: publish-monasca-tempest-plugin-docker-image
     parent: build-monasca-docker-image