Allow signing commits via an SSH key

[winstonrc]

The commit signing docs mention that commits can be signed with GPG keys using GPG_PRIVATE_KEY and GPG_PASSPHRASE.

Could you also enable signing with SSH keys? GitHub allows for ssh keys Telling Git about your SSH key, and SSH signature verification is available in Git 2.34 or later.

[peter-evans]

Hi @winstonrc

I think what we need is an action like crazy-max/ghaction-import-gpg for setting up the SSH key locally. Then the workflow would be very similar to GPG.

Perhaps this one? https://github.com/MrSquaare/ssh-setup-action

If you try and it works, please let me know and we can update the docs!