Based on the python runtimes for 2023.2 [0], we should be running
functional jobs on python 3.9 and python 3.10.

[0] https://governance.openstack.org/tc/reference/runtimes/2023.2.html

Change-Id: Ifc7dc6588af420aa56cd862dd9f558a4506eb1a0

Changes:
- eliminate whitespace in passenv values
- removed skipsdist=True, which in tox 4 appears to prevent os-brick
  from being installed in the testenvs
- made 4.4.1 the tox minversion to catch relevant bugfixes; since
  tox is not constrained, we'll actually be using the most recent
  version of tox 4
- had to adjust the functional testenv's setenv, which wasn't
  overriding OS_TEST_PATH like it did with tox 3
- used generative section names to define the various functional
  py3 testenvs we want to support locally (namely, py38, py39,
  py310, and py311)

This patch makes tox 4 the default so that we can hopefully catch
problems locally before they block the gate.

Change-Id: I01c4d44efa64650cdb46fac34a770a7aa5881baf

We don't need this anymore since all of our jobs are
Python 3.

Change-Id: Ib7e85a72a28ff507cb1371b365b6bfa5fbf70d81

We support 3.10 as of Antelope.

Change-Id: Ia32f0488f4fe90527b1fbd0cb663e33e8537a458

Add file to the reno documentation build to show release notes for
stable/2023.1.

Use pbr instruction to increment the minor version number
automatically so that master versions are higher than the versions on
stable/2023.1.

Sem-Ver: feature
Change-Id: I4d6270b745e171516de982102dbc6e5d9010da19