package/enlightenment: bump to 0.21.8
See https://www.enlightenment.org/news/e0.21.8_release
"We are aware of a issue when running su/sudo under kernel 4.11 the fix
for this issue will be in an upcoming kernel release rather then here
see (https://phab.enlightenment.org/T5470)"
Signed-off-by: Romain Naour <romain.naour@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>