Update python job template

... and supported python runtime versions.

This also makes some changes in tox.ini to adapt to tox 4.

Change-Id: Icc6d7ced31b2e8bd80c6dd52ca54437e5aa35940

setup.cfg

@@ -6,6 +6,7 @@ summary = Collect and cache metadata, run hooks on changes.
 description_file =
 	README.rst
 home_page = https://opendev.org/openstack/os-collect-config
+python_requires = >=3.6
 classifier =
 	Development Status :: 4 - Beta
 	Environment :: Console
@@ -16,8 +17,12 @@ classifier =
 	Operating System :: OS Independent
 	Programming Language :: Python
 	Programming Language :: Python :: 3
+	Programming Language :: Python :: 3 :: Only
 	Programming Language :: Python :: 3.6
 	Programming Language :: Python :: 3.7
+	Programming Language :: Python :: 3.8
+	Programming Language :: Python :: 3.9
+	Programming Language :: Python :: 3.10
 
 [files]
 packages =

tox.ini

@@ -1,7 +1,7 @@
 [tox]
-minversion = 2.0
-skipsdist = True
 envlist = py3,pep8
+ignore_basepython_conflict = True
+minversion = 2.0
 
 [testenv]
 basepython = python3

zuul.d/layout.yaml

@@ -2,4 +2,4 @@
     templates:
       - check-requirements
       - openstack-cover-jobs
-      - openstack-python3-ussuri-jobs
+      - openstack-python3-jobs