tox: remove min_version

3.2 is ancient, so we can just use the default now.

tox.ini

@@ -3,7 +3,6 @@
 
 [tox]
 envlist = py{38,39,310,311,312}-{none,fuse2,fuse3}
-minversion = 3.2
 requires =
 	pkgconfig
 	cython