fix: inline findUpSync util for CJS compatibility

[fmal]

Description

This PR solves #16 by inlining simplified findUpSync util that was previously imported from find-up-simple (https://github.com/sindresorhus/find-up-simple/blob/main/index.js#L32). This caused issues because eslint-config-flat-gitignore was unusable in CJS environment because find-up-simple package is ESM-only.

Nice side effect is that there is only one external dependency now.

Linked Issues

Closes #16

[antfu]

I am actually starting do drop CJS at a whole - I wonder what's the problem that preventing you from going to ESM?

[antfu]

Ok, I see you explained in #16, it's indeed a bug that the CJS is provided but not working. I think I will have your PR and release a patch, while soon going to a new major that drops CJS (so if you still need CJS you can be on 1.x). Does that work for you?

[fmal]

@antfu yeah, that sounds like a good solution (fixing the CJS compatibility on 1.x and then releasing a major that drops it if you wish to do so). Thanks a lot!

I am actually starting do drop CJS at a whole - I wonder what's the problem that preventing you from going to ESM?

My sharable config is also meant to be consumed by some older projects not yet ready for ESM.

[antfu]

My sharable config is also meant to be consumed by some older projects not yet ready for ESM.

If they are already on the flat config, they can just rename the config to .mjs and nothing need to change otherwise.

[fmal]

My sharable config is also meant to be consumed by some older projects not yet ready for ESM.

If they are already on the flat config, they can just rename the config to .mjs and nothing need to change otherwise.

That's a good point. My config is currently hybrid package built with https://github.com/isaacs/tshy (similar to how you used unbuild). But i think in the future i might also drop the hybrid approach and add a note about adding .mjs extension to force ESM.

Thanks for merging ❤️