Bug Unity Update out of date - Key in legacy trusted.gpg

Hi All,

Followed https://docs.unity3d.com/hub/manual/InstallHub.html#install-hub-linux and now every time i runt 'apt update' i get this error;
https://hub.unity3d.com/linux/repos/deb/dists/stable/InRelease: Key is stored in legacy trusted.gpg keyring (/etc/apt/trusted.gpg), see the DEPRECATION section in apt-key(8) for details.

Searches suggest this has been an issue for at least a year. Please update your instructions <3

- Tom