Fix issues related to tox4

Related to https://lists.openstack.org/pipermail/openstack-discuss/2023-February/032247.html

Change-Id: Ie97378271aeb3f98195fbe8433723ea556e9cf9e

tox.ini

@@ -1,8 +1,6 @@
 [tox]
 minversion = 3.2.0
 envlist = py3,pep8
-basepython = python3
-ignore_basepython_conflict = true
 
 [testenv]
 deps =
@@ -21,10 +19,16 @@ commands =
 commands = {posargs}
 
 [testenv:cover]
-commands = python setup.py test --coverage --coverage-package-name=oslo_serialization --testr-args='{posargs}'
+setenv =
+    PYTHON=coverage run --source oslo_concurrency --parallel-mode
+  commands =
+    stestr run {posargs}
+    coverage combine
+    coverage html -d cover
+    coverage xml -o cover/coverage.xml
 
 [testenv:docs]
-whitelist_externals = rm
+allowlist_externals = rm
 deps =
   -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
   -r{toxinidir}/doc/requirements.txt
@@ -33,7 +37,7 @@ commands =
   sphinx-build -W --keep-going -b html doc/source doc/build/html
 
 [testenv:releasenotes]
-whitelist_externals = rm
+allowlist_externals = rm
 deps = {[testenv:docs]deps}
 commands =
   rm -rf releasenotes/build