Release 0.4.0

[NthPortal]

As of #408, our semconv package will be up-to-date with the first officially stable semconv release. I believe this change alone is sufficient reason for a release, as my employer is (and presumably others are) eager to update to using the semantic conventions that have been declared stable. In my view, we should try to get this released as soon as possible.

It's also worth discussing what else we want to get into 0.4.0 or another upcoming release. However, I personally don't think we should delay a release of the updated semconv package for anything—we're still doing pre-releases, and we should happily release often even for minor improvements.

Possible other things worth including in a release soon (please add to the list if you have any suggestions):

• Support using Scala propagators with Java backend #365 just needs a final review and approval I believe
• Proposal: rename package of Java backend #396

Though it is not near release-ability, huge thanks to @iRevive for all their work on the pure-Scala backend (which will be a set of sdk modules).

[iRevive]

will be up-to-date with the first officially stable semconv release

1.23.0 marks HTTP conventions stable. (we are here)

And 1.24 marks JVM metrics stable, but I have no clue how soon the https://github.com/open-telemetry/semantic-conventions-java will catch up.

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So, rather than waiting, we can release 0.4.0 once we decide what to do with #365.

[NthPortal]

thank you for the correction!