Upgrade to otel 0.30

[BSteffaniak]

Hi, I upgraded to the newest opentelemetry 0.30 and it broke compatibility with this crate. This should hopefully fix those incompatibility issues.

Motivation

There were some breaking changes with the upgrade to otel 0.30: https://github.com/open-telemetry/opentelemetry-rust/blob/main/opentelemetry-sdk/CHANGELOG.md#0300

I was able to fix upgrade them without much of an issue. The only compilation issues were in the metrics_publishing test. A few of the types used in that test now require the experimental_metrics_custom_reader feature to be enabled in the opentelemetry-sdk package.

Solution

Bump the versions & fix the one test file that had compilation errors.

Please let me know if I'm missing anything. Thanks!

[BSteffaniak]

There were definitely some weird things with the downcasting that are now potentially problematic with this update. I was able to manually impl AsAny, but after testing (with the metrics_gauge_unstable feature enabled) a bit more it seems like that might not be fully working. I'm not super experienced with std::any::Any (I try to stay away from that), so I might be missing something silly.

[BSteffaniak]

Ok, I think I was able to fix the rest of the AsAny errors. I just needed to fill out the rest of the match arms. It still feels a bit off... but again, I don't really write much AsAny, so I could have done that all wrong.