Merge "Change minversion of tox to 3.18.0"

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-minversion = 3.1.1
+minversion = 3.18.0
 envlist = py39,functional-py39,pep8
 skipsdist = True
 # Automatic envs (pyXX) will use the python version appropriate to that
@@ -10,7 +10,7 @@ ignore_basepython_conflict = True
 [testenv]
 basepython = python3
 usedevelop = True
-whitelist_externals =
+allowlist_externals =
   bash
   rm
   env
@@ -116,7 +116,7 @@ commands =
 [testenv:pdf-docs]
 basepython = python3
 deps = {[testenv:docs]deps}
-whitelist_externals =
+allowlist_externals =
   make
 commands =
   sphinx-build -W -b latex doc/source doc/build/pdf