Rename project

There is now an AUR package named pacman-mirrors created by MSYS2 for WSL. I've submitted a deletion request, but that could take weeks or months to be addressed.

Proposal: Rename pacman-mirrors to manjaro-mirrors.

Users will see an update for pacman-mirrors if they have the AUR enabled in Pamac or use any other AUR helper:

❯ vercmp 4.23.2-2 20221016-1
-1