Prometheus metrics export is missing the SDK version in target_info

[grcevski]

The OTel metrics export correctly report the SDK version used:

semconv.TelemetrySDKVersion(buildinfo.Version)

However the same field is missing when exporting Prometheus metrics in the target info.

[nikhilbhatia08]

Hey @grcevski I would like to pick this issue and try it out. Thanks!

[rafaelroquetto]

Assigned to you @nikhilbhatia08