[tox] Upgrade minimal version of tox

Pierre-Sassoulas · Pierre-Sassoulas · commit 20a1097063df · 2024-10-24T09:56:11.000+02:00
See https://github.com/pytest-dev/pytest-asyncio/pull/970/files\#r1814442641
diff --git a/tox.ini b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-minversion = 3.14.0
+minversion = 4.9.0
 envlist = py39, py310, py311, py312, py13, pytest-min, docs
 isolated_build = true
 passenv =
