patch CI_HUB_TOKEN_PATH with Path instead of str
Should fix the tests for `huggingface_hub==0.10.0rc0` prerelease (see [failed CI](https://github.com/huggingface/datasets/actions/runs/3127805250/jobs/5074879144)). 
Related to [this thread](https://huggingface.slack.com/archives/C02V5EA0A95/p1664195165294559) (internal link).

Note: this should be a backward compatible fix (e.g. works also with previous versions of `huggingface_hub`)

I am not sure where to put the changes so feel free to cherry-pick the commit and close this one without merging.

cc @lhoestq 