libgpiod: bump version to v1.0

libgpiod: bump version to v1.0

This is a major update for libgpiod. The API is not compatible with the
v0.x.y series but since nothing in current buildroot git depends on
this project, I believe we can simply bump the version.

The included tools are compatible with their 0.x.y counterparts.

Signed-off-by: Bartosz Golaszewski <brgl@bgdev.pl>
Reviewed-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Tested-by: Jan Kundrát <jan.kundrat@cesnet.cz>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>