[Feature]: .gitignore in the Nix Flake template

[tad-lispy]

What's missing?

Thank you for jupyenv. It looks very awesome.

I'm new to Jupyter. Presently trying to setup a project to learn it. As I learn I use Git to track my progress. What should I put in the .gitignore file? I did some quick search and looks like .ipynb_checkpoints and */.ipynb_checkpoints/*. But should .jupyter/ directory also go there?

Possible solution

Once we can figure this out, I guess it would be nice to include a recommended .gitignore file in a template.

Alternatives

No response

Additional context

No response

[GTrunSec]

PR is welcome!