net/self-service-password: Update 1.7.3 => 1.8.0

While here, switch to HTTPS MASTER_SITES.

Changelog:
https://github.com/ltb-project/self-service-password/releases/tag/v1.8.0

PR: 295876
Reported by: Krzysztof <ports@bsdserwis.com> (maintainer)
Approved by: osa, vvd (Mentors, implicit)
MFH: 2026Q2