Remove tox skipdist=True

This does not work with latest tox 4.x.
Also makes changes to make tox.ini latest tox
compatible.

Closes-Bug: #2000357
Change-Id: I76666a3931b542e0859be58ae0426cd5f36fb347

tox.ini

@@ -1,6 +1,5 @@
 [tox]
-minversion = 2.0
-skipsdist = True
+minversion = 3.18.0
 envlist = docs,deploy-guide
 
 [testenv]
@@ -21,7 +20,8 @@ commands =
     sphinx-build -a -E -W -d doc/build/doctrees --keep-going -b html doc/source doc/build/html
 
 [testenv:pdf-docs]
-whitelist_externals = make
+allowlist_externals =
+  make
 description =
   Build PDF documentation.
 envdir = {toxworkdir}/docs