The `name` and `description` events were added to `xdg-output` protocol
in version 2 which is part of wayland-protocols 1.14.
In xdg-output-v1 version 3, the `xdg-output.done` event was deprecated
and the `xdg-output.description` event was made mutable, but that
doesn't change the actual events so we do not actually need to require
that version of xdg-output from wayland-protocols 1.18.
Update the wayland-protocols requirement to the bare minimum version,
which is 1.14.
https://gitlab.gnome.org/GNOME/gtk/issues/2057
cairo_req = '>= 1.14.0'
gdk_pixbuf_req = '>= 2.30.0'
introspection_req = '>= 1.39.0'
-wayland_proto_req = '>= 1.12'
+wayland_proto_req = '>= 1.14'
wayland_req = '>= 1.14.91'
graphene_req = '>= 1.9.1'
epoxy_req = '>= 1.4'