This is how I've been doing it: https://stosb.com/blog/using-openpgp-keys-for-ssh-authentica...

Slightly different as I generate a PGP key on the computer and then load it to the Yubikey, which means I can have backup keys with the same secret keys.

I never really got "touch to use" working though, if anyone knows how to do it with GPG keys I'd really appreciate it!