manifest: Untag cairo
manifest: Untag cairo

Now that it builds again.

GNOME/gnome-ostree,vrutkovs/vrutkovs.github.io,GNOME/gnome-ostree,vrutkovs/vrutkovs.github.io,GNOME/gnome-ostree,chergert/gnome-continuous,chergert/gnome-continuous,vrutkovs/vrutkovs.github.io,chergert/gnome-continuous