Fix tox.ini for tox4

Use allowlist_externals instead of whitelist_externals.
Execute shell script with bash.

Depends-on: https://review.opendev.org/866943
Change-Id: Ibb4854595649e9530b9f49b0c74aafc21861d970

tox.ini

@@ -1,7 +1,6 @@
 [tox]
 envlist = py38,pep8
-minversion = 3.2.0
-skipsdist = True
+minversion = 3.18.0
 ignore_basepython_conflict=true
 
 [testenv]
@@ -13,7 +12,7 @@ usedevelop = True
 deps = -c{env:TOX_CONSTRAINTS_FILE:https://releases.openstack.org/constraints/upper/master}
        -r{toxinidir}/requirements.txt
        -r{toxinidir}/test-requirements.txt
-whitelist_externals = *
+allowlist_externals = *
 commands =
          find . -type f -name "*.py[c|o]" -delete
          bash tools/pretty_tox_serial.sh '{posargs}'
@@ -37,7 +36,7 @@ commands = sphinx-build -W -d doc/build/doctrees -b html doc/source doc/build/ht
 [testenv:pdf-docs]
 envdir = {toxworkdir}/docs
 deps = {[testenv:docs]deps}
-whitelist_externals =
+allowlist_externals =
   make
 commands =
   sphinx-build -W -b latex doc/source doc/build/pdf