Update Weston testing information
Once weston!287 (merged) is merged, replace the Weston stuff in https://wayland.freedesktop.org/testing.html with a link to https://wayland.pages.freedesktop.org/weston/ .
Once weston!287 (merged) is merged, replace the Weston stuff in https://wayland.freedesktop.org/testing.html with a link to https://wayland.pages.freedesktop.org/weston/ .