www/rt60: Update 6.0.0 => 6.0.1

Changelog:
https://github.com/bestpractical/rt/releases/tag/rt-6.0.1

• Use https:// for MASTER_SITES
• pt_PT translation no longer exists, only pt and pt_BR.

PR: 288684
Approved by: yuri@ (Mentor)

MFH: 2025Q3
(cherry picked from commit c3a675bb400bf615443c698adaafccf3171a3a79)