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

Partial-Bug: #2000399

Signed-off-by: Al Bailey <al.bailey@windriver.com>
Change-Id: Idd6eab4a194066072ef362be970e5b982665bf43

tox.ini

@@ -29,7 +29,7 @@ commands =
   git restore doc/source/dist_cloud/kubernetes/*
 #  bash hw-updates.sh
   bash htmlChecks.sh doc/build/html
-whitelist_externals = bash
+allowlist_externals = bash
                       htmlChecks.sh
                       get-remote-files.sh
                       git
@@ -40,10 +40,10 @@ deps = {[testenv:docs]deps}
 commands =
   rm -rf api-ref/build
   sphinx-build -W -b html -d api-ref/build/doctrees api-ref/source api-ref/build/html
-whitelist_externals = rm
+allowlist_externals = rm
 
 [testenv:linters]
-whitelist_externals = bash
+allowlist_externals = bash
 commands =
   bash -c "find {toxinidir}                   \
             \( -name .tox -prune \)           \
@@ -61,13 +61,13 @@ passenv=PWD
 commands =
        bash -c "echo Running in {env:PWD}"
        bash new-topic.sh {env:PWD} {toxinidir}
-whitelist_externals = new-topic.sh
+allowlist_externals = new-topic.sh
                       bash
 
 [testenv:picks]
 commands =
        ./pickCompare.sh
-whitelist_externals = pickCompare.sh
+allowlist_externals = pickCompare.sh
                       bash