add django 3.2 on the matrix and remove 3.0 as EOL

tox.ini

@@ -7,9 +7,9 @@ exclude = migrations/*,docs/*
 [tox]
 envlist =
     py35-{2.2},
-    py36-{2.2,3.0,3.1},
-    py37-{2.2,3.0,3.1},
-    py38-{2.2,3.0,3.1,main},
+    py36-{2.2,3.1},
+    py37-{2.2,3.1,3.2},
+    py38-{2.2,3.1,3.2,main},
 
 [gh-actions]
 python =
@@ -24,7 +24,7 @@ commands =
 deps =
     -rrequirements_test.txt
     3.1: Django>=3.1,<3.2
-    3.0: Django>=3.0,<3.1
+    3.2: Django>=3.2,<4.0
     2.2: Django>=2.2,<2.3
     main: https://github.com/django/django/tarball/main
 setenv=