Update Browserify example

[AlecRust]

The Browserify example seems to have been left behind and is no longer relevant:

https://github.com/rollbar/rollbar.js/tree/master/examples/browserify

Could this be updated with your latest recommendations?

[rivkahstandig3636]

Thanks for pointing this out! We'll update.

[glortho]

+1. It'd also help folks if you brought back a Webpack example.