github-ssh-signing

1. Generate a new SSH key.

   ssh-keygen -t ed25519 -c "your_comment"
   

2. Configure Git.

   git config gpg.format ssh
   git config user.signingKey "~/.ssh/id_ed25519.pub"
   git config commit.gpgsign true

3. Add the SSH public key to GitHub.
   You should select the key type as Signing Key.

   cat ~/.ssh/id_ed25519.pub
   # GitHub > Settings > SSH and GPG keys > New SSH key