clean up last "import six" (apache#1197)

a-detiste · dkropachev · commit 1042cd74eafd · 2025-03-05T09:30:44.000-04:00
diff --git a/docs/upgrading.rst b/docs/upgrading.rst
@@ -351,7 +351,3 @@ The following dependencies have officially been made optional:
 
 * ``scales``
 * ``blist``
-
-And one new dependency has been added (to enable Python 3 support):
-
-* ``six``
