Fix RTD buile fails - tox.ini whitelist->allowlist

Issue-ID: NONRTRIC-855
Change-Id: Ib1d192ace1198f937c6deb4ddac360a2a2a74f57
Signed-off-by: JohnKeeney <john.keeney@est.tech>
diff --git a/tox.ini b/tox.ini
index 2705e16..00dd3b8 100644
--- a/tox.ini
+++ b/tox.ini
@@ -29,7 +29,7 @@
 commands =
     sphinx-build -W -b html -n -d {envtmpdir}/docs/doctrees ./docs/ {toxinidir}/docs/_build/html
     echo "Generated docs available in {toxinidir}/docs/_build/html"
-whitelist_externals = echo
+allowlist_externals = echo
 
 [testenv:docs-linkcheck]
 basepython = python3