grpc-js example has missing dependency

[reggiemcdonald]

Please answer these questions before submitting a bug report.

What version of OpenTelemetry are you using?

0.9.0

What version of Node are you using?

v14.4.0

What did you do?

Ran the grpc-js example located here.

What did you expect to see?

The example should run.

What did you see instead?

An error is thrown because module grpc could not be found.

Additional context

The compiled proto files require 'grpc' which wont work because the example uses grpc-js. You can see the import here:

opentelemetry-js/examples/grpc-js/helloworld_grpc_pb.js

Lines 19 to 22 in ab62a4d

	'use strict';
	const grpc = require('grpc');
	const helloworld_pb = require('./helloworld_pb.js');

The grpc team has realeased a tool to fix this issue called grpc-tools. So this problem could be resolved by recompiling the proto files with that.

Alternatively, instead of working with compiled protocol buffers, it would also work to use the proto-loader.

[reggiemcdonald]

I can fix this if someone can assign me to it