Embed AppImage update information

[shuvashish76]

When trying via AppImageUpdate

This is a common standard for updating AppImages.
AppImage having update information would also recognized by other software e.g. AppImageLauncher

info:

• https://github.com/AppImageCommunity/AppImageUpdate#update-information-overview
• https://github.com/AppImage/AppImageSpec/blob/master/draft.md#update-information

[kevinaboos]

Sounds like a good idea, thanks for the suggestion!

We currently don't have an update pipeline or the ability to push updates out to package managers, but we'll certainly aim to do so in the future. However, I'm not sure if I necessarily have direct control over this, because we currently use cargo-packager to generate the AppImage (and other distributable formats), so it might be best to file an issue with them to see if they have a tool-level solution.

[shuvashish76]

Also do checkout this guide: https://github.com/ivan-hc/AppImage-tips