Fallback to 3.6

Author: juhasch

tox.ini

@@ -12,10 +12,10 @@ envlist =
 [testenv]
 basepython =
     pypy: {env:TOXPYTHON:pypy}
-    py37: {env:TOXPYTHON:python3.7}
-    {docs,spell}: {env:TOXPYTHON:python3.7}
-    {appveyorartifacts,bump,check,clean,codecov,coveralls,lint,report,pypi_build,pypi_upload}: {env:TOXPYTHON:python3.7}
-    {condarecipe}: {env:TOXPYTHON:python3.7}
+    py36: {env:TOXPYTHON:python3.6}
+    {docs,spell}: {env:TOXPYTHON:python3.6}
+    {appveyorartifacts,bump,check,clean,codecov,coveralls,lint,report,pypi_build,pypi_upload}: {env:TOXPYTHON:python3.6}
+    {condarecipe}: {env:TOXPYTHON:python3.6}
 setenv =
     PYTHONPATH={toxinidir}/tests
     PYTHONUNBUFFERED=yes