db.instance.id Semantic Convention

[arielvalentin]

db.instance.id replaces the custom db.mysql.instance.address attribute as of merging the following PR:

open-telemetry/semantic-conventions#345

This attribute is currently used by the Trilogy instrumentation.

[dlahn]

@arielvalentin Should this be added here first? https://github.com/open-telemetry/opentelemetry-ruby/blob/main/semantic_conventions/lib/opentelemetry/semantic_conventions/trace.rb

[arielvalentin]

@dlahn we have had a few discussions about the continued use of the Semantic Conventions gem and I think we have all but decided to abandon its use in its current form.

We do not have an easy way right now to do things like Schema Versions nor do we emit schema URLs as part of the instrumentation scope, so you cannot really tell what version of the semconv schema an instrumentation is using.

In addition to that the gem itself does not support multiple schema versions or alternative pre-1.0 semconv compatibility envars.

For now we are moving forward with the use of string literals.

If this is an area where you would like to help us, we welcome your contributions!

cc: @robbkidd