update python-checker test to allow Python3.8
#
[tox]
-envlist = py27,py35,py36,py37
+envlist = py27,py35,py36,py37,py38
skipsdist = True
minversion = ${TOX_VERSION}
skip_missing_interpreters = True
@@ -54,3 +54,6 @@ basepython = python3.6
[testenv:py37]
basepython = python3.7
+[testenv:py38]
+basepython = python3.8
+
