release: initial gRPC instrumentation release under the OpenTelemetry org

[michal-kazmierczak]

This PR provides the final touches for the gRPC instrumentation release. It (probably) closes #1261

I checked the release automation but I'm unsure how the automated release should be handled given that this gem was donated and older versions exist on RubyGems. Could I get some guidance on this?

Also, I think we will be able to add this gem to all once the initial release is done.

[arielvalentin]

If this is the first real release of the gem then set the version to 0.0.0 and use the default changelog heading that is generated from here:

https://github.com/open-telemetry/opentelemetry-ruby-contrib/blob/main/.instrumentation_generator/templates/CHANGELOG.md.tt

The release tooling should pick up all related PRs and metion them as part of the initial changlog.

[michal-kazmierczak]

If this is the first real release of the gem then set the version to 0.0.0 and use the default changelog heading that is generated from here:

https://github.com/open-telemetry/opentelemetry-ruby-contrib/blob/main/.instrumentation_generator/templates/CHANGELOG.md.tt

The release tooling should pick up all related PRs and metion them as part of the initial changlog.

Thanks for your help. I think we are all set now for the automation.