tox.ini: Fix 'requires' for autoprovisioning on tox 3

Author: Matthias Koeppe

tox.ini

@@ -131,7 +131,8 @@ envlist =
 requires =
     # For repaired numerical factors in tox 4, need >= 4.2.7.
     # Because of https://github.com/tox-dev/tox/issues/3238, need <4.14.1
-    tox>=4.2.7, tox<4.14.1
+    tox>=4.2.7
+    tox<4.14.1
 
 skipsdist = true