Allow for additional PyPI index-urls

[davegallant]

Is there an option to fetch from a custom PyPI or specify multiple index-urls?

For example

pur --index-url https://pypi.internal/simple -r requirements.txt

[alanhamlett]

No, but let's add --index-url as an array argument to support this. Should be as simple as passing the list of index urls to pip here:

pip-update-requirements/pur/__init__.py

Line 333 in 8ef5197

session=session, find_links=[], index_urls=[PyPI.simple_url])

[alanhamlett]

Also note that --index-url is supported in requirements.txt files:

tests/samples/requirements-with-alt-index-url.txt