as some packages in the installer move to AUR, I wrote a small script named fix-packages-xml to work around the problem.
It can be used like:
fix-packages-xml gamin xorg-mkfontdir
Now I put the script to github with instructions: https://github.com/manuel-192/Antergos/tree/master/antergos-installer-fixes
Should be easier to use than ever, just download and run!