build(ci): clean tox envs

tox.ini

@@ -6,10 +6,8 @@ exclude = .tox,docs/modeltranslation/conf.py
 [tox]
 distribute = False
 envlist =
-    py{27,34,35,36}-1.11,
-    py{34,35,36}-2.0,
-    py{35,36,37}-2.1,
-    py{36,37}-3.0,
+    py{36,37,38}-2.2,
+    py{36,37,38}-3.0,
 
 [testenv]
 downloadcache = {toxworkdir}/_download/
@@ -17,15 +15,10 @@ commands =
     django-admin.py --version
     {envpython} runtests.py {posargs}
 basepython =
-    py27: python2.7
-    py34: python3.4
-    py35: python3.5
     py36: python3.6
     py37: python3.7
+    py38: python3.8
 deps =
-    1.11: Django==1.11.*
-    2.0: Django==2.0.*
-    2.1: Django==2.1.*
     2.2: Django==2.2.*
     3.0: Django>=3.0a1,<3.1
     Pillow