Add tox-py311 job

Python 3.11 is out now. Add a tox-py3.11 base job to make it easier to
run tests on this new release of Python.

Change-Id: I19c98c0e683e36f727ae869e7b60f7c16d7eb78d

zuul-tests.d/project.yaml

@@ -13,6 +13,8 @@
             nodeset: ubuntu-focal
         - tox-py310:
             nodeset: ubuntu-jammy
+        - tox-py311:
+            nodeset: ubuntu-jammy
     gate:
       jobs:
         - zuul-tox-docs
@@ -23,6 +25,8 @@
             nodeset: ubuntu-focal
         - tox-py310:
             nodeset: ubuntu-jammy
+        - tox-py311:
+            nodeset: ubuntu-jammy
     promote:
       jobs:
         - zuul-promote-docs

zuul.d/python-jobs.yaml

@@ -192,6 +192,17 @@
       tox_envlist: py310
       python_version: "3.10"
 
+- job:
+    name: tox-py311
+    parent: tox
+    description: |
+      Run unit tests for a Python project under cPython version 3.11.
+
+      Uses tox with the ``py311`` environment.
+    vars:
+      tox_envlist: py311
+      python_version: "3.11"
+
 - job:
     name: tox-docs
     # This is not parented to tox since we do not need