Document requirement for Debian compression zstd

The compression algorithm _ZSstandard_ for Debian *binary* packages is
only supported by Debian since `dpkg >= 1.12.18` available with Debian
12 "Bookworm" released in 2023-06:
<https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=892664>

For Ubuntu the earlies version I found is Ubuntu 18.04 "Bionic Beaver"
released in 2018-04:
<https://launchpad.net/ubuntu/+source/dpkg/1.19.0.5ubuntu2>

`zstd` is used by default since Ubuntu 21.10. The Gitlab Debian package
registry will not recognize such binary packages as valid and fails with
> Invalid Package: failed metadata extraction

Changelog: other

Closes #422584

doc/user/packages/debian_repository/index.md

@@ -27,6 +27,9 @@ Prerequisites:
 - The `dpkg-deb` binary must be installed on the GitLab instance.
   This binary is usually provided by the [`dpkg` package](https://wiki.debian.org/Teams/Dpkg/Downstream),
   installed by default on Debian and derivatives.
+- Support for compression algorithm ZStandard requires version `dpkg >=
+  1.21.18` from Debian 12 Bookworm or `dpkg >= 1.19.0.5ubuntu2` from Ubuntu
+  18.04 Bionic Beaver.
 
 ## Enable the Debian API **(FREE SELF)**