Release 0.15.0

[abonander]

New feature release:

• tracing and OpenTelemetry integration
• zstd compression
• Access to X-ClickHouse-Summary header from server response

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!

[loyd]

It seems (according to 0.14 -> 0.15 bump) that a new version contains breaking changes, but the CHANGELOG doesn't reflect them

[abonander]

@loyd we decided that the integration of tracing was a significant enough behavior change that it warranted a major version bump. We thought new spans and logs magically appearing in trace output might be a little confusing if it happened in a patch release. I suppose an MSRV bump is potentially in order as well, but none of these changes required any new language features.