Fix tox files

tox.ini

@@ -0,0 +1,50 @@
+[tox]
+requires =
+    tox>=4.2
+    tox-uv>=1.11.3
+envdir = {toxinidir}/.venv
+args_are_paths = false
+envlist =
+    py39-{4.2},
+    py310-{4.2,5.0,5.1,main},
+    py311-{4.2,5.0,5.1,main},
+    py312-{4.2,5.0,5.1,main},
+    py313-{4.2,5.0,5.1,main},
+    docs,
+    lint
+
+[testenv]
+basepython =
+    py39: python3.9
+    py310: python3.10
+    py311: python3.11
+    py312: python3.12
+    py313: python3.13
+usedevelop = true
+pip_pre = true
+setenv =
+    PYTHONPATH={toxinidir}
+    PYTHONWARNINGS=all
+commands =
+    python manage.py test {posargs}
+deps =
+    4.2: Django==4.2.*
+    5.0: Django==5.0.*
+    5.1: Django==5.1.*
+    main: https://github.com/django/django/archive/main.tar.gz
+
+[testenv:lint]
+basepython = python3.12
+allowlist_externals = just
+setenv =
+    PYTHONWARNINGS=default
+commands =
+    just lint
+
+[testenv:docs]
+basepython = python3.12
+allowlist_externals = just
+setenv =
+    PYTHONWARNINGS=default
+commands =
+    just docs