Update testing of python versions

As per the current release tested runtime, we test
from python 3.9 till 3.11 and python 3.12 as non voting
so updating the fundtional tests job as well as python
classifier. Unit test jobs are already handled by the
general job template.

Depends-On: https://review.opendev.org/c/openstack/openstack-zuul-jobs/+/918946

Change-Id: I4240315e0676f458f6d0eb5439073fd013eac086

.zuul.yaml

@@ -7,23 +7,27 @@
       - openstackclient-plugin-jobs
     check:
       jobs:
-        - openstack-tox-functional-py38:
-            required-projects:
-              - openstack/placement
         - openstack-tox-functional-py39:
             required-projects:
               - openstack/placement
         - openstack-tox-functional-py310:
             required-projects:
               - openstack/placement
+        - openstack-tox-functional-py311:
+            required-projects:
+              - openstack/placement
+        - openstack-tox-functional-py312:
+            voting: false
+            required-projects:
+              - openstack/placement
     gate:
       jobs:
-        - openstack-tox-functional-py38:
-            required-projects:
-              - openstack/placement
         - openstack-tox-functional-py39:
             required-projects:
               - openstack/placement
         - openstack-tox-functional-py310:
             required-projects:
               - openstack/placement
+        - openstack-tox-functional-py311:
+            required-projects:
+              - openstack/placement

setup.cfg

@@ -17,9 +17,9 @@ classifier =
     Programming Language :: Python :: Implementation :: CPython
     Programming Language :: Python :: 3 :: Only
     Programming Language :: Python :: 3
-    Programming Language :: Python :: 3.8
     Programming Language :: Python :: 3.9
     Programming Language :: Python :: 3.10
+    Programming Language :: Python :: 3.11
 
 [files]
 packages =

tox.ini

@@ -39,13 +39,6 @@ deps =
   openstack-placement>=1.0.0
 commands = stestr --test-path=./osc_placement/tests/functional run {posargs}
 
-[testenv:functional-py38]
-description =
-  Run functional tests using python3.8.
-deps = {[testenv:functional]deps}
-commands =
-  {[testenv:functional]commands}
-
 [testenv:functional-py39]
 description =
   Run functional tests using python3.9.
@@ -60,6 +53,19 @@ deps = {[testenv:functional]deps}
 commands =
   {[testenv:functional]commands}
 
+[testenv:functional-py311]
+description =
+  Run functional tests using python3.11.
+deps = {[testenv:functional]deps}
+commands =
+  {[testenv:functional]commands}
+
+[testenv:functional-py312]
+description =
+  Run functional tests using python3.12.
+deps = {[testenv:functional]deps}
+commands =
+  {[testenv:functional]commands}
 
 [testenv:pep8]
 description =