Add auth to snapshot download

[lewtun]

This PR adds a use_auth_token argument to snapshot_download so private repos can be downloaded from the Hub.

Usage

from huggingface_hub import snapshot_download

# Download with explicit token
filepath = snapshot_download("some-private-repo", use_auth_token="api_XXX")
# Download with token from cache
filepath = snapshot_download("some-private-repo", use_auth_token=True)

[LysandreJik]

Thanks for working on the implementation @lewtun, this was an oversight!

[lewtun]

I'm not sure why the unit tests are failing since they seem to be unrelated to the changes in this PR 🤔

[osanseviero]

Re: failing tests, some are unfortunately flaky at the moment :( You can try to re-run the workflows.

Code looks good to me, it would be great if you add some unit tests. You can use private in Repository to make a private repo. Then you could have a test without token that shows that the command fails, and another one with token that shows it works.

[lewtun]

Code looks good to me, it would be great if you add some unit tests. You can use private in Repository to make a private repo. Then you could have a test without token that shows that the command fails, and another one with token that shows it works.

Thanks for the tips and suggestions - the new unit test should cover the three possible values of use_auth_token in snapshot_download

[osanseviero]

Looks good to me! Thanks a lot

[lewtun]

@LysandreJik this PR is ready for a final pass / approval on your side :)

[LysandreJik]

Looks great, thank you for iterating @lewtun!

[LysandreJik]

Will do a release containing this commit later today.