Units 1 and 6: Fix for installing notebook dependencies

[AnotherPianist]

Fixes #251, #253, and #255.

Currently, this notebook can't be run because of an error while installing the dependencies.

The error comes from trying to install the stable-baselines3 package. They are aware of this bug and working on it for the next version. Their current workaround is to use the 65.5.0 version of setuptools by running pip install setuptools==65.5.0. For more information, see DLR-RM/stable-baselines3#1324.

Adding the line setuptools==65.5.0 at the top of the requirements-unit6.txt file doesn't solve the problem since pip doesn't have a way to install packages in order (see pypa/pip#2362).

Therefore, the solution is to add a new code cell to the notebook to run pip install setuptools==65.5.0 before installing requirements-unit6.txt.

[AnotherPianist]

The same issue is happening in the notebook from Unit 1.

As a solution, the same code cell is added to notebook 1.

Fixes #253 and #255.

[nikohou]

This helped thanks!

[osanseviero]

Approving and merging so things are not broken in the incoming days

[osanseviero]

Thanks a lot for this fix!! 🔥

[HuggingFaceDocBuilderDev]

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