update xdg-shell client protocol

Update the xdg-shell client protocol to the one included in
wayland-protocols 1.39 .

This prevent the following error when using the xdg-shell protocol:
  interface 'xdg_toplevel' has no event 3

It was updated using the relevant wayland-scanner commands from
the wayland-protocols make target in a Debian Buster container
against the xdg-shell.xml file included in version 1.39.