update tox

Author: auvipy

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = py35-django{1.8,1.9,1.10}, flake8
+envlist = py35-django{1.11,1.10}, py36-django{1.11}, py37-django{1.11,2.2}
 
 [testenv]
 sitepackages = False
@@ -9,16 +9,12 @@ deps =
     django1.8: Django>=1.8.0,<1.9.0
     django1.9: Django>=1.9.0,<1.10.0
     django1.10: Django>=1.10.0,<1.11.0
+    django1.11: Django>=1.11.17,<2.0
+    django2.2: Django>=2.2.17,<3.0
 
 setenv =
     PYTHONPATH={toxinidir}/tests
     DJANGO_SETTINGS_MODULE=settings
 commands =
     {envpython} -Wall tests/manage.py test {posargs}
 
-[testenv:flake8]
-basepython = python2.7
-deps =
-    flake8
-commands =
-    flake8 djcelery