This reverts commit 8535f841487968be7105c280201ca275c6934333.

Keeping Python 3.10 in setup.cfg classifier. 

Reason for revert:

Needed-By: https://review.opendev.org/c/openstack/openstack-zuul-jobs/+/882175

TC has been discussing about re-adding the python 3.8
testing in current master 2023.2 release testing.

- https://meetings.opendev.org/meetings/tc/2023/tc.2023-04-25-18.00.log.html#l-191
- https://lists.openstack.org/pipermail/openstack-discuss/2023-April/033469.html

While governance changes are under review, TC agreed to add py3.8 testing
so that we do not see more project/lib dropping python 3.8 and make them
uninstalable on python 3.8

- https://meetings.opendev.org/meetings/tc/2023/tc.2023-05-02-18.00.log.html#l-17
- https://review.opendev.org/c/openstack/governance/+/882165

Also adding py3.8 testing back in job https://review.opendev.org/c/openstack/openstack-zuul-jobs/+/882175

Change-Id: Ie1d0a1ce0439ca5ffe3d3d377f3ac14a4fa6702f

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: I7f5323109ab03cdf3bd36fabee1bee37e7887679

This library has been used by several OpenStack projects and we can
safely assume this is not mature and can be used for production.

Change-Id: I26540b2d887d2a5e9208a08dc3d2b4ce149924ac

Fix Sphinx 6.0 doc build error.

Change-Id: I9a1571cf416d32d040d8ff05d1c8b1769d1d0558

* convert_unicode engine option is no longer supported
* use positional arguments for select, lists are no longer supported
* insert no longer accepts keyword constructor arguments
* explicitly convert Rows to dicts

Change-Id: I858d60b3d142e8ade8b2c0154872c8bfc19a42ba