appimageupdatetool Error checking for changes

[JulianGro]

When running appimageupdatetool on an AppImage I just created, I get:

motofckr9k@motofckr9k-mint-desktop:~/Vircadia$ ./appimageupdatetool-x86_64.AppImage -j Vircadia-x86_64-release-latest.AppImage
qt5ct: using qt5ct plugin
zsync2: 
zsync2: Reading and/or parsing .zsync file failed!
Error checking for changes!motofckr9k@motofckr9k-mint-desktop:~/Vircadia$ 

There is no clear indication of what the problem is. Personally I don't even know if the update information actually made it into the AppImage properly.

[JulianGro]

So apparently you can check the update information of an AppImage with ./*.AppImage --appimage-updateinfo
This revealed that the URL was just wrong. We should really be getting a "404 Not Found" back when this happens.