Suggestion: Unify creates commits with information of what was updated in the flake.lock

[NovaViper]

This is just for helpful info to look back on whenever there's issues with a flake update, so you can look back at what the previous version was for a particular input (and perhaps pin it to that version) until whatever issue is resolved.

[llakala]

I've thought of this - I would need a way to gather that info. Maybe nix flake update has a JSON output flag.