boot/shim: bump to version 16.0
For release note, see:
https://github.com/rhboot/shim/releases/tag/16.0
Signed-off-by: Julien Olivain <ju.o@free.fr>
Signed-off-by: Peter Korsgaard <peter@korsgaard.com>
(cherry picked from commit 7c0da583138645baddce292a067d4ba82257d495)
Signed-off-by: Thomas Perale <thomas.perale@mind.be>