allow auth with headers

[davidszotten]

would you be open to allowing passing auth headers, eg something along the lines of https://github.com/pypa/pip/issues/8042

[zanieb]

Thanks for the request! I'm not sure when we'll be able to support this, but we will consider it.

For my own notes, xref to a "blocking" reason in pip: https://github.com/pypa/pip/pull/8078#issuecomment-657037943

[davidszotten]

yes it sounds like having this configured per _host as opposed to per _index is one solution to the security issue

[nwp90]

We need this in pip, and I'd like to point out that different auth per-host is not enough - for git repositories it's quite likely that bearer tokens would be configured per-repository. If uv allowed this, we'd be switching right now.