i3: Bump to 4.8

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>
i3[~scm]: Update dependencies

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>
i3lock: Update (and fix) dependencies

Signed-off-by: Quentin Glidic <sardemff7+git@sardemff7.net>