add missing dependencies for browsers

[DylanVann]

If this package is intended to be used in browsers it should not require node builtins.

Instead it should use browser compatible dependencies, e.g.:

• https://www.npmjs.com/package/util
• https://www.npmjs.com/package/events

If you try to use this package with a bundler (e.g. some Rollup setups, and Vite) that is strict about this sort of thing you will be forced to workaround this issue.

I've also opened a PR on twilio-webrct.js.

Contributing to Twilio

All third-party contributors acknowledge that any contributions they provide will be made under the same open-source license that the open-source project is provided under.

• I acknowledge that all my contributions will be made under the project's license.

[bpinto]

We are having the same incompatibility raised by Webpack 5, would be nice if someone could have a look at this PR.