Requirements.txt file is not parsed correctly per documentation

A `requirements.txt` file with the global options at the top of the file like so:
```
--index-url https://aws:${CODEARTIFACT_AUTH_TOKEN}@${DOMAIN}-${ACCOUNT_ID}.d.codeartifact.us-east-1.amazonaws.com/pypi/private-releases/simple/
--extra-index-url https://aws:${CODEARTIFACT_AUTH_TOKEN}@${DOMAIN}-${ACCOUNT_ID}.d.codeartifact.us-east-1.amazonaws.com/pypi/public-pypi/simple/
```

[This issue](https://github.com/pypa/pip/issues/11511) mentions that the `--index-url` seems like it must be first.

It seems like the parsing doesn't support it for now, although, it may be part of a third party library.

[Relevant pip requirements.txt documentation](https://pip.pypa.io/en/stable/reference/requirements-file-format/#supported-options)