Hotfix: update huggingface_hub dependency version

[abidlabs]

As part of #6616, some of the backend tests now need a valid hf token to run. These can be specified via the HF_TOKEN environment variable, or by logging in via the hf-cli. In the GitHub CI runners, we use the HF_TOKEN variable, so we use the former approach. However, this requires huggingface_hub>=0.19.3 since in previous versions, the huggingface_hub library looked for a different environment variable called HUGGING_FACE_HUB_TOKEN

[gradio-pr-bot]

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Install Gradio from this PR

pip install https://gradio-builds.s3.amazonaws.com/ea454e5f508dac9072d86006c7b60294d80256ea/gradio-4.8.0-py3-none-any.whl

Install Gradio Python Client from this PR

pip install "gradio-client @ git+https://github.com/gradio-app/gradio@ea454e5f508dac9072d86006c7b60294d80256ea#subdirectory=client/python"

[gradio-pr-bot]

🦄 change detected

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gradio	patch
gradio_client	patch

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Hotfix: update huggingface_hub dependency version

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