Add requirements for dlt+ tutorial

[VioletM]

Documentation description

Some of the libraries are missing:
NumPy, pandas, pyarrow
So we need to add a line saying:

Please, install the following libraries:
pip install numpy pandas pyarrow

Are you a dlt user?

None

[sh-rp]

One note: There is a chance these dependencies already are in the project, but I am not sure. Meaning that they will be available when dlt+ is installed.

[Soot3]

Open to take this on. test and make the change. Maybe a conditional note @sh-rp