[documentation] - in python, user needs to use environment variable instead of "replacing `YOUR_API_KEY` in code"

[gusmith-ambiata]

Hi AICodePal (and @giorgiop ),

I have observed a small difference between the python use and the documentation you are maintaining.
Since #3 , when using the python library, the code is reading the api key to use through the OPENAI_API_KEY environment variable. But the README is still stating (in the python section)

Replace YOUR_API_KEY in the ai_code_pal.py file with your actual ChatGPT API key.

Could you update it to specify that a user should use the environment variable instead?

And maybe for the future, you may want to check that the documentation stays up to date when new pull requests are merged.