Update tox.ini with Django 4.2, Python 3.11 (#233)

tox.ini

@@ -2,7 +2,7 @@
 envlist =
     # list of supported Django/Python versions:
     py{37,38,39,py3}-dj{32}
-    py{38,39,310}-dj{40,41,main}
+    py{38,39,310,311}-dj{40,41,42,main}
     py38-{lint,docs}
 
 [gh-actions]
@@ -11,6 +11,7 @@ python =
     3.8: py38
     3.9: py39
     3.10: py310
+    3.11: py311
     pypy3: pypy3
 
 [testenv]
@@ -19,6 +20,7 @@ deps =
     dj32: django>=3.2,<4.0
     dj40: django>=4.0,<4.1
     dj41: django>=4.1,<4.2
+    dj42: django>=4.2,<4.3
     djmain: https://github.com/django/django/archive/main.tar.gz
 usedevelop = True
 commands =