package/libinput: fix legal info

package/libinput: fix legal info

Commit a87d99af2f88eb2755959163727584f673483748 forgot to update hash
of COPYING which was updated to replace master by main reference with
https://gitlab.freedesktop.org/libinput/libinput/-/commit/354df8bce9874e92de2ad8535fdcedaec0755b27

Fixes:
 - http://autobuild.buildroot.org/results/b82d53ac70737488dd780a7112fc7ea0153768ba

Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Reviewed-by: Peter Seiderer <ps.report@gmx.net>
Signed-off-by: Yann E. MORIN <yann.morin.1998@free.fr>