sysutils/pacman: update to 6.0.2

New to this version is the archlinux FLAVOR to manage an Arch Linux
userland for the Linuxulator. It installs into/manages /compat/archlinux
to not conflict with the linux-c7 ports, similar to sysutils/debootstrap.

Reviewed by: fluffy, trasz
Event: BSDCan 2022
Event: SouthEast LinuxFest 2022
Event: SouthEast LinuxFest 2023
Differential Revision: https://reviews.freebsd.org/D33652