Mosaic's CI

[marc2332]

I was looking at the logs when the CI was failing (https://github.com/mlajtos/mosaic/runs/1015926152?check_suite_focus=true):

And saw the issue appeared when it was building for pacman, so I tried removing pacman as target, and it worked: https://github.com/marc2332/mosaic/runs/1023121099?check_suite_focus=true

On a "normal" ubuntu, it would need external dependencies to build for RPM and Pacman, but for some reason Github already provides these, at least to build for RPM, I am not sure if for Pacman too