Fix 404 link to the pyporting mailing list (GH-27320)

Co-authored-by: Mariatta Wijaya <[email protected]>
Co-authored-by: Łukasz Langa <[email protected]>
(cherry picked from commit 977d99d)

Co-authored-by: Rohit Nishad <[email protected]>

Author: miss-islington

Doc/howto/pyporting.rst

@@ -20,8 +20,8 @@ Porting Python 2 Code to Python 3
    came into existence, you can read Nick Coghlan's `Python 3 Q & A`_ or
    Brett Cannon's `Why Python 3 exists`_.
 
-   For help with porting, you can email the python-porting_ mailing list with
-   questions.
+
+   For help with porting, you can view the archived python-porting_ mailing list.
 
 The Short Explanation
 =====================
@@ -446,7 +446,7 @@ to make sure everything functions as expected in both versions of Python.
 
 .. _pytype: https://github.com/google/pytype
 .. _python-future: http://python-future.org/
-.. _python-porting: https://mail.python.org/mailman/listinfo/python-porting
+.. _python-porting: https://mail.python.org/pipermail/python-porting/
 .. _six: https://pypi.org/project/six
 .. _tox: https://pypi.org/project/tox
 .. _trove classifier: https://pypi.org/classifiers