Add zsync information

[clin1234]

This file is used to provide binary delta updates for the OnlyOffice AppImage, since there is no other update mechanism on such version.
The command to create the zsync file goes as follows: appimagetool <path to .desktop file> -u "gh-release|<username>|<repo name>|latest|<name of appimage>".

Probably wise to put this in as a GitHub Action. Source: https://github.com/AppImage/AppImageSpec/blob/master/draft.md#github-releases

[ShockwaveNN]

Hi, thanks for your idea

I've created issue 56591 in our private issue tracker to discuss it with our team

But personally, I don't think there is a point in that, we release our product not very often, I think once in several months and no a log of people will be downloading smaller updates just to save several hundred of megabytes

But maybe our team is thinking different

[clin1234]

Status?

[ShockwaveNN]

Sorry, no news

I don't think we'll implement this feature soon, so I cannot promise anything