Add backward compatibility check mode

[lmolkova]

Implements back-compat checks against released version
See open-telemetry/semantic-conventions#740 for the context

Usage:

-f path/to/semantic-conventions/model compatibility --previous-version 1.24.0

If I run it against current semconv main, I get

Found 5 compatibility issues:
                 attribute 'system.processes.status': was removed
                 metric 'system.processes.count': was removed
                 metric 'system.processes.created': was removed
                 attribute 'container.labels': was removed
                 attribute 'k8s.pod.labels': was removed

[jsuereth]

This is a great additiion! Thanks for putting this together.

• I echo Alexandra's concerns around download success. However, I don't feel the need to reapprove on fix.
• I had one other comment on additioinal stability checking we can do, but consider it non-blocking.

[joaopgrassi]

This is great! Thanks for working on it.

Just a question I had while reviewing/reading the issue: Who is the target group of this new task in the tool? Like, when is it going to be executed? During a release of semconv? By SDK authors? Ran automatically as part of a CI/CD in semconv? It's not clear and maybe this should be stated somewhere?

[lmolkova]

@joaopgrassi my intention is to add it to CI checks - here's draft PR that demonstrates it open-telemetry/semantic-conventions#764