package/xscreensaver: bump to version 6.03

xlib_libXft and xlib_libXi are now mandatory

https://www.jwz.org/xscreensaver/changelog.html



Signed-off-by: Fabrice Fontaine <fontaine.fabrice@gmail.com>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>