Bump opentelemetry-instrumentation-ethon from 0.21.5 to 0.21.6

Bumps [opentelemetry-instrumentation-ethon](https://github.com/open-telemetry/opentelemetry-ruby-contrib) from 0.21.5 to 0.21.6.
- [Release notes](https://github.com/open-telemetry/opentelemetry-ruby-contrib/releases)
- [Changelog](https://github.com/open-telemetry/opentelemetry-ruby-contrib/blob/main/instrumentation/ethon/CHANGELOG.md)
- [Commits](open-telemetry/opentelemetry-ruby-contrib@opentelemetry-instrumentation-ethon/v0.21.5...opentelemetry-instrumentation-ethon/v0.21.6)

---
updated-dependencies:
- dependency-name: opentelemetry-instrumentation-ethon
  dependency-type: indirect
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

Gemfile.lock

@@ -275,7 +275,7 @@ GEM
     opentelemetry-instrumentation-delayed_job (0.22.2)
       opentelemetry-api (~> 1.0)
       opentelemetry-instrumentation-base (~> 0.22.1)
-    opentelemetry-instrumentation-ethon (0.21.5)
+    opentelemetry-instrumentation-ethon (0.21.6)
       opentelemetry-api (~> 1.0)
       opentelemetry-common (~> 0.21.0)
       opentelemetry-instrumentation-base (~> 0.22.1)