package/ncdu: bump to version 1.18
For change log since 1.17, see:
- https://dev.yorhel.nl/ncdu/changes
This commit also adds md5 and sha1 hashes published on the web site.
Signed-off-by: Julien Olivain <ju.o@free.fr>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>