mail/opensmtpd: update to 7.6.0p1 portable release (+)
Release Notes: https://github.com/OpenSMTPD/OpenSMTPD/releases/tag/7.4.0p0 \
https://github.com/OpenSMTPD/OpenSMTPD/releases/tag/7.4.0p1 \ https://github.com/OpenSMTPD/OpenSMTPD/releases/tag/7.5.0p0 \ https://github.com/OpenSMTPD/OpenSMTPD/releases/tag/7.6.0p0 \ https://github.com/OpenSMTPD/OpenSMTPD/releases/tag/7.6.0p1