README update needed

[sidwellr]

With the release of p5.js version 2, a few changes are needed to the README.md file:

It looks like the documentation can now be found at https://beta.p5js.org/reference/p5.sound/ (on the p5 version 2 website).

I don't think p5.sound is included in p5.js anymore. When using the p5 editor to change versions, if version 2.x is selected and p5.sound.js is turned on, it adds a CDN link to p5.sound@0.2.0 directly. I don't know exactly what the plan is, but the text under Latest Build needs updating.

Finally, it might be useful for the README to mention explicitly that this version of p5.sound is compatible with p5.js version 2.

[kunstewi]

hey @ksen0 I was planning to work on this, but I guess you will be handling this one. So should I stop working on it since you're handling it, or raise a PR within a day or two ?