apt-key keyring deprecated

[MadWalnut]

Hi,

in Ubuntu 22.04 LTS apt-key is deprecated. Installing via the provided repo install instructions in README works, but results in this warning shown every time apt update is run:

W: https://archive.heckel.io/apt/dists/debian/InRelease: Key is stored in legacy trusted.gpg keyring (/etc/apt/trusted.gpg), see the DEPRECATION section in apt-key(8) for details.

This can be easily be fixed by adding the public key via signed-by. See here.

Maybe update the README to make the install process simpler for new users?

Thanks for the great program.

[binwiederhier]

Thank you!