`--find-links` in `requirements.txt` not handled

[fviernau]

For example, the library torch==2.0.0+cpu is not on pypi. It can however be installed by passing an URL pointing to an HTML page via --find-links to pip`.

This can be done inside a requirements.txt as follows:

-f https://download.pytorch.org/whl/cpu/torch_stable.html
torch==2.0.0+cpu

So, for above requirements.txt, python inspector is unable to "resolve" the dependencies.

[fviernau]

I've meanwhile found that there is supported implemented for --extra-index-url[1]. This can be used as a work around in this case. At least if #143 is fixed, which I stumbled across.

[1] https://github.com/nexB/python-inspector/commit/b66aa71660f93b5b1994a747dd5f002f157b512a