Proposal: upgrade otelgin's semconv to 1.27

[flc1125]

Problem Statement

I hope to upgrade the otel semconv from 1.20 to 1.27.

But I am currently facing a problem. Because it depends on semconvutil, which is also version 1.20.

Proposed Solution

I plan two solutions to address it:

• Just upgrade otelgin. Keep semconvutil at version 1.20.
• Upgrade both otelgin and semconvutil to 1.27. However, this might break other components like otelecho. Therefore, it means they need to be upgraded together.

In the long run, choosing option 2 would be better. However, my personal suggestion is to carry out the upgrade in a "gradual" manner.

That is to say: through multiple iterations, uniformly upgrade all components that use semconvutil and perform a unified merge.

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I would like to understand everyone's thoughts and suggestions.

[dmathieu]

There are breaking changes in this semconv upgrade.
We should probably follow the same process as for otelhttp.

See #5132