Mark the specification as obsolete since the effort moved to OpenTelemetry

[zihotki]

It would be great to mention that the specification is obsolete (sort of) and it's going to be replaced by OpenTelemetry

[vanHoesel]

I think that is a very bad idea.

The specification is not obsolete at all, the OpenTracing project on itself is still current, OpenTelemetry is not yet fully supported across all platforms and or services.

Marking it 'Obsolete' sends out the wrong signal as if this is 'replaced', it is not