update python and django versions (#787)

Author: auvipy

tox.ini

@@ -2,11 +2,10 @@
 envlist =
 	py37-flake8,
 	py37-docs,
-	py38-django{30,22,21,20},
-	py37-django{30,22,21,20},
-	py36-django{22,21,20},
-	py35-django{22,21,20},
-	py34-django20,
+	py38-django{30,22,21},
+	py37-django{30,22,21},
+	py36-django{22,21},
+	py35-django{22,21},
 # FIXME: something is broken in DRF integration, enable once fixed
 #	py38-djangomaster,
 #	py37-djangomaster,
@@ -22,7 +21,6 @@ setenv =
 	PYTHONPATH = {toxinidir}
 	PYTHONWARNINGS = all
 deps =
-	django20: Django>=2.0,<2.1
 	django21: Django>=2.1,<2.2
 	django22: Django>=2.2,<3
 	django30: Django>=3.0a1,<3.1