isc-dhcp-client is being phased out in Debian, and it was recently
removed from forky/testing due to https://bugs.debian.org/1106121.
For releases with codename trixie and before select isc-dhcp-client,
otherwise select dhcpcd-base. This way the dhcp-client installed in the
container matches the one that comes with the respective release by default.
This change was discussed at https://bugs.debian.org/1125011.
Signed-off-by: Arnaud Rebillout <arnaudr@debian.org>
