Drop Py2.7, 3.5 and Django 1.11, 2.0, 2.1, 3.0

tox.ini

@@ -1,16 +1,12 @@
 [tox]
 envlist =
-    py27-django111
-    py{35,36,37,38}-django{111,20,21}
-    py{35,36,37,38,39}-django22
-    py{36,37,38,39}-django{30,31,32}
+    py{36,37,38,39}-django22
+    py{36,37,38,39}-django{31,32}
     lint
     coverage
 
 [gh-actions]
 python =
-    2.7: py27
-    3.5: py35
     3.6: py36
     3.7: py37
     3.8: py38
@@ -21,16 +17,12 @@ commands = ./manage.py test --no-input {posargs}
 extras = test
 pip_pre = true
 deps =
-    django111: django>=1.11,<2.0
-    django20: django>=2.0,<2.1
-    django21: django>=2.1,<2.2
     django22: django>=2.2,<2.3
-    django30: django>=3.0,<3.1
     django31: django>=3.1,<3.2
     django32: django>=3.2,<3.3
 
 [testenv:lint]
-basepython = python3.6
+basepython = python3.8
 deps =
     -r requirements/dev.txt
 commands =