fix: use the right github-cli arch package

[lu-jim]

Problem

When running bin/setup in an arch-based system, without the github-cli installed, the script will try to run

sudo pacman -S --noconfirm gh

Which is not the right package and thus the setup fails with the following error:

The Solution

For Arch Linux, the right command based on the github-cli documentation is:

sudo pacman -S --noconfirm github-cli