Merge branch 'switch-to-geoip-mirror' into 'master'

Switch to GeoIP mirror

See merge request archlinux/archlinux-docker!60

rootfs/etc/pacman.d/mirrorlist

-Server = https://mirror.pkgbuild.com/$repo/os/$arch
+Server = https://geo.mirror.pkgbuild.com/$repo/os/$arch
 Server = https://mirror.rackspace.com/archlinux/$repo/os/$arch
 Server = https://mirror.leaseweb.net/archlinux/$repo/os/$arch