Document requirement for ZStandard compression

What does this MR do and why?

Document requirement to support ZStandard compression for Debian binary packages.

Since dpkg 1.21.18 compression zstd is supported. It 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

Document requirement to support zstd.

#422584

Screenshots or screen recordings

How to set up and validate locally

• Enable Debian API for this project by an Administrator until #337288 is resolved.
• See sample project https://gitlab.com/pmhahn/debian-package-registry

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

doc/api/packages/debian_group_distributions.md

@@ -166,8 +166,8 @@ POST /groups/:id/-/debian_distributions
 | `version`                     | string         | no       | The version of the new Debian distribution. |
 | `description`                 | string         | no       | The description of the new Debian distribution. |
 | `valid_time_duration_seconds` | integer        | no       | The valid time duration (in seconds) of the new Debian distribution. |
-| `components`                  | architectures  | no       | The new Debian distribution's list of components. |
-| `architectures`               | architectures  | no       | The new Debian distribution's list of architectures. |
+| `components`                  | string array   | no       | The new Debian distribution's list of components. |
+| `architectures`               | string array   | no       | The new Debian distribution's list of architectures. |
 
 ```shell
 curl --request POST --header "PRIVATE-TOKEN: <your_access_token>" "https://gitlab.example.com/api/v4/groups/5/-/debian_distributions?codename=sid"
@@ -213,8 +213,8 @@ PUT /groups/:id/-/debian_distributions/:codename
 | `version`                     | string         | no       | The Debian distribution's new version. |
 | `description`                 | string         | no       | The Debian distribution's new description. |
 | `valid_time_duration_seconds` | integer        | no       | The Debian distribution's new valid time duration (in seconds). |
-| `components`                  | architectures  | no       | The Debian distribution's new list of components. |
-| `architectures`               | architectures  | no       | The Debian distribution's new list of architectures. |
+| `components`                  | string array   | no       | The Debian distribution's new list of components. |
+| `architectures`               | string array   | no       | The Debian distribution's new list of architectures. |
 
 ```shell
 curl --request PUT --header "PRIVATE-TOKEN: <your_access_token>" "https://gitlab.example.com/api/v4/groups/5/-/debian_distributions/unstable?suite=new-suite&valid_time_duration_seconds=604800"