Replace deprecated tox.ini option

This option was replaced in 2020, deprecated, and eventually removed in
tox 4. The correct option already appears elseware in this tox.ini file.

This fix is necessary to run `tox -e doc` per the README.md
instructions on tox 4.

Signed-off-by: Eric Searcy <[email protected]>

Author: emsearcy

tox.ini

@@ -88,7 +88,7 @@ commands_pre =
 [testenv:doc]
 basepython = python3
 usedevelop = False
-whitelist_externals = make
+allowlist_externals = make
 deps = sphinx
 commands =
     sphinx-apidoc -E -o docs/actor dapr/actor