Bug#892664: dpkg: Please add support for zstd (Zstandard) compressed packages

[Marcel Partap]

Dear Guillem et al.,
don't know whether there already has been that called-for discussion on debian-devel 
about the technical burden of zstd support in dpkg. But obviously, ubuntu's move to 
compress debs with zstd by default in July last year (in favor of better UX) has made 
picking packages from their (or any third-party) repository (like their rtl8821ce-dkms) 
"a bit more difficult". And it seems somewhat unlikely they will roll back that 
decision..

So here's the patch rebased again on current git tip.
https://salsa.debian.org/mpartap-guest/dpkg/-/tree/zstd-rebased

Best Regards
Marcel 😅