Git clone should be one of the steps

I was surprised to see that I need to run `pip install -r requirements.txt` while I didn't even have the repository downloaded.

There are many ways to distribute GitHub projects: via releases with installers, cloning the repo, running curl | sh, etc.

Although it's probably obvious, it should be written.

For example:
https://github.com/ggerganov/whisper.cpp?tab=readme-ov-file#quick-start