Consider pushing spec changes to SIGs as issues in repos

We got the following feedback in the last end user working group (which was attended by SIG maintainers):

Would be nice if spec changes were somehow pushed out to SIGs. Tigran recently notified each SIG about instrumentation spec changes by creating an issue on each SIG’s repo - this was incredibly helpful!

One possibility is to automate creation of issues in language repos for each new CHANGELOG entry (either when the PR with the CHANGELOG is merged or when a spec release is made). To make this automatable we may need to first automate CHANGELOG.md creation from structured data (e.g. using the chloggen tool that Collector uses). We have an open issue for this: https://github.com/open-telemetry/opentelemetry-specification/issues/655

Before we go ahead with this I would like to check with maintainers to see if this is desirable by (most?) maintainers. There is a danger that if implemented poorly we may spam the repos by too many issues. We will probably need to have some sort of annotation in changelog entries to indicate if it needs to create issues for language repos.