mail/py-authheaders: update to 0.15.2

Submitter becomes maintainer. Already maintainer of other ports.

Changelog: https://github.com/ValiMail/authentication-headers/releases/tag/0.15.2

PR: 272375
MFH: 2023Q3
(cherry picked from commit 60916596e07218c5eff4c6f36cd70387b37839ba)