README: fix s/libwayland/libweston/ typo

Since one is (about to be) using libweston, they should check for it as
opposed to libwayland.

Silly copy/paste mistake that would have caused a lot of confusion.

Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Quentin Glidic <sardemff7+git@sardemff7.net>
1 file changed