Update iso/preseeds/preseed.cfg

change repository component `non-free` to the newly created `non-free-firmware` repository as of Debian 12.0.0 as we don't need all non-free software, just the `non-free-firmawre` which is now separated out

Author: alexpeterson91

iso/preseeds/preseed.cfg

@@ -25,7 +25,7 @@ d-i mirror/country string manual
 d-i mirror/http/hostname string deb.debian.org
 d-i mirror/http/directory string /debian
 d-i mirror/http/proxy string
-d-i apt-setup/local0/repository string http://deb.debian.org/debian/ bookworm main contrib non-free
+d-i apt-setup/local0/repository string http://deb.debian.org/debian/ bookworm main contrib non-free-firmware
 d-i apt-setup/cdrom/set-first boolean false
 d-i apt-setup/cdrom/set-next boolean false   
 d-i apt-setup/cdrom/set-failed boolean false