Update README for opentelemetry-tracer package

[mayurkale22]

Similar to #96

[kaushikchaubal]

Hi @mayurkale22 , I am happy to pick this up but not sure what exactly needs to be updated in the README.

I saw the two readme.md files in the opentelemetry-basic-tracer and opentelemetry-node-tracer packages. They have a TODO to demonstrate API. Is that what is expected to be updated?

I am keen to start contributing to this community so any help with this will be appreciated.

[mayurkale22]

Actually, I have modified the tracer README.md files in #134 and #135. Demonstrate API section can be added later.

Meantime, feel free to look up-for-grabs Good for taking. Extra help will be provided by maintainers issues for contributions. Also, we have gitter channel https://gitter.im/open-telemetry/opentelemetry-node where we discuss few stuff. I would suggest joining channel to get involved in node/js project.

Thanks for the interest in OpenTelemetry project!

[mayurkale22]

Closed via #134, I will open another issue to add an example.