Updates readme to avoid #169

[Desislav-Petrov]

Make sure #169 is avoided when following the readme

[JSoet]

Just to mention, I think that the readme isn't intended to have these steps, I think that the built output is meant to be included in the git repo:

The quickest way to get started is to run the pre-built client bundle:

I think it was removed here: https://github.com/Netflix/flamescope/commit/742753b557ada3e41b907d76360a8437bbd36c5f

@spiermar was that done on purpose? Or was it by accident because those files were added to gitignore?

Edit: this is caused by this: https://github.com/Netflix/flamescope/issues/150

[spiermar]

It was on purpose. A workflow should take care of building the client on new commits, but seems like it's not working. I need to investigate this a bit further.