wayland-egl: bump the version number to 18.1.0

Seems like I was overoptimistic with my earlier assumption, namely:

"... 17.3.x should be the last version that ships the library."

Mesa 18.0.0 and its wayland-egl is about to be released any time soon,
so bump the number since it must no be smaller. As soon as we get
a wayland release I'll drop the Mesa copy but for now.

Signed-off-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Daniel Stone <daniels@collabora.com>