Moves supported python runtimes from version 3.8 to 3.10

Within 2023.2 python version 3.9 and 3.10 are the
supported python runtimes [1].
[1] https: //review.opendev.org/c/openstack/governance/+/872232

Change-Id: Ibd9c332ea54bc225887ceb60e77622432793726f

.zuul.yaml

@@ -2,7 +2,7 @@
     templates:
       - check-requirements
       - lib-forward-testing-python3
-      - openstack-python3-antelope-jobs
+      - openstack-python3-jobs
       - periodic-stable-jobs
       - publish-openstack-docs-pti
       - release-notes-jobs-python3

setup.cfg

@@ -6,7 +6,7 @@ description_file =
 author = OpenStack
 author_email = openstack-discuss@lists.openstack.org
 home_page = https://docs.openstack.org/oslo.config/latest/
-python_requires = >=3.8
+python_requires = >=3.9
 classifier =
     Development Status :: 5 - Production/Stable
     Environment :: OpenStack
@@ -16,8 +16,8 @@ classifier =
     Operating System :: OS Independent
     Programming Language :: Python
     Programming Language :: Python :: 3
-    Programming Language :: Python :: 3.8
     Programming Language :: Python :: 3.9
+    Programming Language :: Python :: 3.10
     Programming Language :: Python :: 3 :: Only
     Programming Language :: Python :: Implementation :: CPython