Adds dependencies to pyproject.toml so you can run the CLI with uvx

[snth]

I simply ran uv add -r requirements.txt.

This enables you to run the project without installing with:

uvx --from git+https://github.com/snth/markdown-crawler.git@uvx markdown-crawler

[JoeCotellese]

Wow, didn't know uv could do that.

[snth]

Any reason you don't want to merge this PR?

[snth]

Oh, I see the README edit was specific to my fork. I can update that.