opentelemetry-proto tar archive contains spurious files

[marcalff]

The file opentelemetry-proto-1.4.0.tar.gz contains the following:

• buf.yaml
• package.json
• package-lock.json

which are also present in git in the opentelemetry-proto repository.

These do not look like items that should be maintained in git, and should be removed.

[tigrannajaryan]

The reason this happens is that the current release process does not have a build step. It simply ends up packing the entire repo's content into the release file.