Update CC80: Voice Chatbot with p5.Speech

[dipamsen]

Updated code to use promises

@shiffman This has a mixed usage of .then().catch() and async-await in order to keep the code as similar to the video as possible.

The file loading was earlier using callbacks so I changed it to .then(); whereas getting the reply was earlier completely synchronous and now returns promises, so I used await.

Let me know if this is fine or anything needs to be changed.

[kfahn22]

There are some minor differences with the sketch on the CT account. The sketch links to the latest version of p5 p5@1.5.0 and the p5.speech CDN and the rive script is named 'brain.txt'.

[shiffman]

It's good to use brain.rive instead brain.txt (I think?) but the web editor won't allow for the rive file extension!