Update README with import instructions and how to build / test

[MikeGoldsmith]

Closed #476.

[paivagustavo]

Hey @MikeGoldsmith, thanks for picking this up!

As I've already stated, I'm -1 on remove the instructions to go get the lib.

It works just fine for the main use case of the OpenTelemetry Go which is adding the lib to a project when using Go modules, which is the recommended dependency management by the Go language team.

Anyway, If others are fine with these changes I'll not try to block it in any way.

[krnowak]

Suggested change

	All packages are published to [https://pkg.go.dev/go.opentelemetry.io/otel](https://pkg.go.dev/go.opentelemetry.io/otel) and is the preferred location to import from.
	All packages are published to [go.opentelemetry.io/otel](https://pkg.go.dev/go.opentelemetry.io/otel) and is the preferred location to import from.

My suggestion would also be to add links to https://blog.golang.org/using-go-modules and https://golang.org/cmd/go/#hdr-Add_dependencies_to_current_module_and_install_them as pointers about adding a dependency to the project.

[krnowak]

I think that this basically duplicates what's written in CONTRIBUTING.md, so instead of having ## Building the code section, I'd move the ## Contributing section from below to here. And then modify the CONTRIBUTING.md file to remove the go get invocation.

[paivagustavo]

+1 for not adding this Building the code since we already have the Contributing and it is harder to maintain two files that have similar content.

[krnowak]

Hey @MikeGoldsmith, thanks for picking this up!

As I've already stated, I'm -1 on remove the instructions to go get the lib.

It works just fine for the main use case of the OpenTelemetry Go which is adding the lib to a project when using Go modules, which is the recommended dependency management by the Go language team.

go get is a way to add deps to the project, true. But I don't think that our README.md should be talking about it at all - I suggested adding links to some golang blog post and docs, which is a superior source of information about how to add a dependency. Using go get as a way to get sources to contribute is already considered legacy, so I'm proposing removing it in favor of git clone from CONTRIBUTING.md.

[paivagustavo]

go get is a way to add deps to the project, true. But I don't think that our README.md should be talking about it at all - I suggested adding links to some golang blog post and docs, which is a superior source of information about how to add a dependency.

In my experience it is very handy to have the go get ... command on the readme, it helps experienced Go programmers to quickly get started with a lib and use it. This is very a very common pattern and I think we should follow it, if you take a look the biggest Go libs almost all of them have this instruction at the top of the README.md.

It is interesting to link docs and blogs about go modules. I would just ask ourselves, what are the expected audience of the Otel Go? I don't think it is someone who is new to Go. I'm not opposing to that but I don't think it also necessary.

Using go get as a way to get sources to contribute is already considered legacy, so I'm proposing removing it in favor of git clone from CONTRIBUTING.md.

Totally agree. I'm in favor of changing the CONTRIBUTING.md but not the README.md

[MikeGoldsmith]

I'll remove building the code section from README and update CONTRIBUTING.md with build instructions.