Fixes the several problems/errors caused by tox

Change-Id: Ia9665f075bbd55a078be1b95da1c535707985877

test-requirements.txt

@@ -14,3 +14,4 @@ stestr>=1.0.0 # Apache-2.0
 pylint==1.4.5 # GPLv2
 testscenarios>=0.4 # Apache-2.0/BSD
 testtools>=2.4.0 # MIT
+sahara>=10.0.0.0b1

tox.ini

@@ -1,6 +1,6 @@
 [tox]
-envlist = py38,pep8
-minversion = 3.1.1
+envlist = pep8
+minversion = 3.18.0
 skipsdist = True
 # this allows tox to infer the base python from the environment name
 # and override any basepython configured in this file
@@ -18,7 +18,10 @@ deps =
     -r{toxinidir}/requirements.txt
     -r{toxinidir}/test-requirements.txt
 commands = stestr run {posargs}
-passenv = http_proxy HTTP_PROXY https_proxy HTTPS_PROXY no_proxy NO_PROXY
+passenv =
+    http_proxy
+    https_proxy
+    no_proxy
 
 [testenv:debug-py36]
 basepython = python3.6
@@ -48,7 +51,7 @@ deps =
 commands =
     rm -rf doc/build/html
     sphinx-build -W -b html doc/source doc/build/html
-whitelist_externals =
+allowlist_externals =
     rm
 
 [testenv:pdf-docs]
@@ -57,7 +60,7 @@ commands =
     rm -rf doc/build/pdf
     sphinx-build -W -b latex doc/source doc/build/pdf
     make -C doc/build/pdf
-whitelist_externals =
+allowlist_externals =
     make
     rm
 
@@ -68,7 +71,7 @@ deps =
 commands =
   rm -rf releasenotes/build releasenotes/html
   sphinx-build -a -E -W -d releasenotes/build/doctrees -b html releasenotes/source releasenotes/build/html
-whitelist_externals = rm
+allowlist_externals = rm
 
 [testenv:debug]
 # It runs tests from the specified dir (default is sahara_plugin_spark/tests)