Add job to test with SQLAlchemy master (2.x)

Change-Id: Ib5ba66ba32dd1b2981be338682556018fc41826c
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>

.zuul.yaml

@@ -18,6 +18,7 @@
         - openstack-tox-functional-py38
         - openstack-tox-functional-py39
         - openstack-tox-pep8
+        - placement-tox-py310-with-sqlalchemy-2x
         - placement-nova-tox-functional-py39
         - placement-nested-perfload:
             voting: false
@@ -67,6 +68,21 @@
         - placement-nova-tox-functional-py39
         - tempest-integrated-placement
 
+- job:
+    name: placement-tox-py310-with-sqlalchemy-2x
+    parent: openstack-tox-py310
+    description: |
+      Run unit tests with main branch of SQLAlchemy, alembic and oslo.db.
+      Takes advantage of the base tox job's install-siblings feature.
+    # The job only tests the latest and shouldn't be run on the stable branches
+    branches: master
+    required-projects:
+      - name: github.com/sqlalchemy/sqlalchemy
+        override-checkout: main
+      - name: github.com/sqlalchemy/alembic
+        override-checkout: main
+      - name: openstack/oslo.db
+
 - job:
     name: placement-nova-tox-functional-py39
     parent: nova-tox-functional-py39