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

Change-Id: Ia7c5235f822d5c3516b7d300e6ccc3dbc1823c3f
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>

.zuul.yaml

@@ -1,3 +1,18 @@
+- job:
+    name: freezer-tox-py311-with-sqlalchemy-2x
+    parent: openstack-tox-py311
+    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
+
 - project:
     templates:
       - check-requirements
@@ -10,8 +25,10 @@
         - openstack-tox-pylint
         - freezer-tempest-basic
         - freezer-tempest-basic-sql
+        - freezer-tox-py311-with-sqlalchemy-2x
     gate:
       jobs:
         - openstack-tox-pylint
         - freezer-tempest-basic
         - freezer-tempest-basic-sql
+        - freezer-tox-py311-with-sqlalchemy-2x