Deprecated dependencies

#### To Reproduce
Follow instructions in `INSTALL.md`. (Side note: pytorchvideo on PyPI is missing `cat_all_gather` so `pip install git+https://github.com/facebookresearch/pytorchvideo` was used instead of `pip install pytorchvideo`)

> Searching for sklearn
> Reading https://pypi.org/simple/sklearn/
> Downloading https://files.pythonhosted.org/packages/46/1c/395a83ee7b2d2ad7a05b453872053d41449564477c81dc356f720b16eac4/sklearn-0.0.post12.tar.gz#sha256=54cff9e20839b7b202321178228af4d9388bedf78425d9299fd9ee170d68802e
> Best match: sklearn 0.0.post12
> Processing sklearn-0.0.post12.tar.gz
> Writing /tmp/easy_install-v4umg4se/sklearn-0.0.post12/setup.cfg
> Running sklearn-0.0.post12/setup.py -q bdist_egg --dist-dir /tmp/easy_install-v4umg4se/sklearn-0.0.post12/egg-dist-tmp-nv6yndio
> error: Setup script exited with The 'sklearn' PyPI package is deprecated, use 'scikit-learn'
> rather than 'sklearn' for pip commands.
>
> Here is how to fix this error in the main use cases:
> - use 'pip install scikit-learn' rather than 'pip install sklearn'
> - replace 'sklearn' by 'scikit-learn' in your pip requirements files
> (requirements.txt, setup.py, setup.cfg, Pipfile, etc ...)
> - if the 'sklearn' package is used by one of your dependencies,
> it would be great if you take some time to track which package uses
> 'sklearn' instead of 'scikit-learn' and report it to their issue tracker
> - as a last resort, set the environment variable
> SKLEARN_ALLOW_DEPRECATED_SKLEARN_PACKAGE_INSTALL=True to avoid this error

More information is available at
https://github.com/scikit-learn/sklearn-pypi-package

and

> Searching for PIL
> Reading https://pypi.org/simple/PIL/
> No local packages or working download links found for PIL
> error: Could not find suitable distribution for Requirement.parse('PIL')

after replacing "sklearn" with "scikit-learn" in `setup.py`

#### Expected behavior
Installs SlowFast.

#### Environment
Red Hat Enterprise Linux Server release 7.9 (Maipo), Python 3.10.14, gnu/11.2.0