Linux - Embed AppImage update information

[shuvashish76]

AppImage Delta updates

When trying to update via AppImageUpdate

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

info:

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

Updating will take less amount of data and time due to downloading only diff.
Lots of projects already support updating AppImage e.g: LibreWolf, KeePassXC, Sigil etc.

[siddharthvaddem]

Feel free to raise a PR. I was not aware that you can update AppImage without using some electron dependency.

[shuvashish76]

I'm not a dev, please see https://github.com/ivan-hc/AppImage-tips