Git-based conditional commands

[Southclaws]

This may be out of scope as it can be accomplished with a script.

But I hate scripts. Especially *sh scripts.

So it would be neat to run certain commands only if specific directories have been touched with a commit. This would be beneficial for monorepos.

Consider:

frontend/
backend/

When backend is changed, you want to run docker-compose up --build -d and when frontend is changed, you want to run npm build or something.

My use case is that a project has a backend hosted on a machine and a frontend hosted on Vercel. So when changes are made to the frontend, Pico doesn't need to run a build for the backend.