Support pyproject.toml files

Currently OSV-Scanner does not support pyproject.toml files.

Example: https://github.com/huggingface/datatrove/blob/main/pyproject.toml

I am not familiar with how many projects use a pyproject.toml file for dependencies management so I can't speak to the impact of this enhancement. At the same time, it seems like an easy file to extract the dependencies from.