x11/libxkbcommon: Update to 1.0.1

Update x11/libxkbcommon to 1.0.1
This adds features to manage custom layouts in local files, rather than
system files.
It also adds a tool to inspect and debug keymaps.
Changelog and announcement:
https://lists.freedesktop.org/archives/wayland-devel/2020-September/041596.html