correct way to check GPG signature - Stellarium AppImage

I thought the Stellarium AppImage was corrupted or changed, and submitted an issue - https://github.com/Stellarium/stellarium/issues/3432

It turns out the correct way to check files in stellarium releases is mentioned on https://github.com/Stellarium/stellarium/releases/

It's not the AppImage signing method as mentioned at
https://docs.appimage.org/packaging-guide/optional/signatures.html#validating-the-signature

So, not

./Stellarium-0.19.3-x86_64.AppImage --appimage-signature

but

gpgv --keyring ./stellarium.gpg 
    Stellarium-0.19.3-x86_64.AppImage.asc 
      Stellarium-0.19.3-x86_64.AppImage