chore(deps): bump opentelemetry-sdk from 1.5.0 to 1.6.0

Bumps [opentelemetry-sdk](https://github.com/open-telemetry/opentelemetry-ruby) from 1.5.0 to 1.6.0.
- [Release notes](https://github.com/open-telemetry/opentelemetry-ruby/releases)
- [Changelog](https://github.com/open-telemetry/opentelemetry-ruby/blob/main/sdk/CHANGELOG.md)
- [Commits](open-telemetry/opentelemetry-ruby@opentelemetry-sdk/v1.5.0...opentelemetry-sdk/v1.6.0)

---
updated-dependencies:
- dependency-name: opentelemetry-sdk
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <support@github.com>

Gemfile.lock

@@ -323,7 +323,7 @@ GEM
       opentelemetry-semantic_conventions (>= 1.8.0)
     opentelemetry-registry (0.3.1)
       opentelemetry-api (~> 1.1)
-    opentelemetry-sdk (1.5.0)
+    opentelemetry-sdk (1.6.0)
       opentelemetry-api (~> 1.1)
       opentelemetry-common (~> 0.20)
       opentelemetry-registry (~> 0.2)