Update tox.ini to work with tox 4

This change will allow this repo to pass zuul now
that this has merged:
https://review.opendev.org/c/zuul/zuul-jobs/+/866943

Tox 4 deprecated whitelist_externals.
Replace whitelist_externals with allowlist_externals
Tox 4 Fail on pass_env/passenv entries containing whitespace.
Updated passenv with comma separated values
Closes-Bug: #2000727

Change-Id: I48859d5a1c8242a6a7d049c96f8dcabbf4c7c044

tox.ini

@@ -1,7 +1,6 @@
 [tox]
 envlist = py3,pep8
 minversion = 2.0
-skipsdist = True
 ignore_basepython_conflict = True
 
 [testenv]
@@ -11,7 +10,13 @@ install_command = pip install {opts} {packages}
 setenv = VIRTUAL_ENV={envdir}
          PYTHONDONTWRITEBYTECODE = 1
          PYTHONWARNINGS=default::DeprecationWarning
-passenv = http_proxy HTTP_PROXY https_proxy HTTPS_PROXY no_proxy NO_PROXY
+passenv =
+    http_proxy
+    HTTP_PROXY
+    https_proxy
+    HTTPS_PROXY
+    no_proxy
+    NO_PROXY
 deps =
   -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
   -r{toxinidir}/test-requirements.txt
@@ -22,19 +27,23 @@ commands =
   rm -f .testrepository/times.dbm
   find . -type f -name "*.pyc" -delete
   stestr run --slowest {posargs}
-whitelist_externals =
+allowlist_externals =
   rm
   find
 
 [testenv:unit-postgresql]
 setenv = VIRTUAL_ENV={envdir}
 passenv = ZUUL_PROJECT
-commands = ./run_tests.sh -N --db-type postgresql
+allowlist_externals =
+  bash
+commands = bash run_tests.sh -N --db-type postgresql
 
 [testenv:unit-mysql]
 setenv = VIRTUAL_ENV={envdir}
 passenv = ZUUL_PROJECT
-commands = ./run_tests.sh -N --db-type mysql
+allowlist_externals =
+  bash
+commands = bash run_tests.sh -N --db-type mysql
 
 [testenv:pep8]
 commands =
@@ -80,7 +89,7 @@ commands =
 deps =
   -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
   -r{toxinidir}/doc/requirements.txt
-whitelist_externals =
+allowlist_externals =
   make
 commands =
   sphinx-build -W -b latex doc/source doc/build/pdf
@@ -97,7 +106,8 @@ commands =
 commands =
   rm -rf api-ref/build
   sphinx-build -W --keep-going -b html -d api-ref/build/doctrees api-ref/source api-ref/build/html
-whitelist_externals = rm
+allowlist_externals =
+  rm
 
 #Skip PEP257 violation.
 [flake8]