Support commit signing with SSH key

[julius-boettger]

Description

I would like to be able to sign commits using an SSH key, which is possible since Git 2.34.0.

Motivation

I use SSH key authentication for Git, which makes it natural to also want to use this for commit signing.

I am already doing this using the command line for GitHub (following this guide) and would like to do it using JGit too, mainly because I like to use Gitnuro, which uses JGit. There's an an issue over at Gitnuro for this too.

Alternatives considered

I have considered...

• not signing my commits at all
• signing them with GPG instead

Additional context

No response