chore: update from opentelemetry-sdk 0.28.0 to 0.29.0

[alessandrobologna]

Motivation

This PR updates the dependencies from opentelemetry 0.28.0 to 0.29.0. The update requires adapting to breaking changes in the SpanExporter trait interface, which now requires immutable references (&self instead of &mut self) and uses async fn syntax rather than returning BoxFuture.

Solution

• Updated opentelemetry dependencies from 0.28.0 to 0.29.0 in Cargo.toml
• Updated all SpanExporter trait implementations in test files and examples to match the breaking changes in the 0.29.0 release:
  • Changed &mut self to &self in method signatures
  • Changed return type from BoxFuture<'static, OTelSdkResult> to using async fn that returns OTelSdkResult directly
  • Removed unnecessary BoxFuture imports
• Updated CHANGELOG.md with the breaking change

The specific breaking changes in opentelemetry-sdk 0.29.0 that affected this crate are documented in the upstream changelog:

Breaking The SpanExporter::export() method no longer requires a mutable reference to self. Before:
async fn export(&mut self, batch: Vec<SpanData>) -> OTelSdkResult
After:
async fn export(&self, batch: Vec<SpanData>) -> OTelSdkResult

All tests and examples have been verified to build and run correctly with these changes.

[djc]

Thanks! Looks like we this might also need an MSRV adjustment...

[djc]

Thanks! Looks like we this might also need an MSRV adjustment...

Never mind, the MSRV was already high enough. Just fix the formatting!

[alessandrobologna]

Sorry, I missed that, pushed another commit with the formatting fix. Thank you.

[tisonkun]

Can we have a release for this patch?

[djc]

Sure - can you submit a PR with a version bump?