Stop creating /etc/timezone
/etc/localtime got turned into a symlink in 2016a-1 (see bug #803144), now that /usr gets mounted from the initrd.
This now leaves /etc/timezone completely redundant, as you should get exactly the same answer by readlink /etc/localtime -- and if you do not get the same answer, you have an inconsistency. /etc/localtime obviously "wins" for the actual clock (as that's what programs are reading), but you presumably get the /etc/timezone value in some "system configuration tool" packages which read /etc/timezone first. As /etc/timezone is a Debianism and /etc/localtime the distro-agnostic standard, tzdata 2022g-3 stopped creating /etc/timezone, but kept updating /etc/timezone if present.
So also stop creating /etc/timezone
on new installations.
Closes: #1030850