Bump io.opentelemetry.instrumentation:opentelemetry-instrumentation-bom-alpha

Bumps [io.opentelemetry.instrumentation:opentelemetry-instrumentation-bom-alpha](https://github.com/open-telemetry/opentelemetry-java-instrumentation) from 2.14.0-alpha to 2.15.0-alpha.
- [Release notes](https://github.com/open-telemetry/opentelemetry-java-instrumentation/releases)
- [Changelog](https://github.com/open-telemetry/opentelemetry-java-instrumentation/blob/main/CHANGELOG.md)
- [Commits](https://github.com/open-telemetry/opentelemetry-java-instrumentation/commits)

---
updated-dependencies:
- dependency-name: io.opentelemetry.instrumentation:opentelemetry-instrumentation-bom-alpha
  dependency-version: 2.15.0-alpha
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

pom.xml

@@ -20,7 +20,7 @@
         <automatic.module.name>--module-name-need-to-be-overriden--</automatic.module.name>
         <guava.version>33.4.6-jre</guava.version>
         <junit-jupiter.version>5.12.1</junit-jupiter.version>
-        <otel.instrumentation.version>2.14.0-alpha</otel.instrumentation.version>
+        <otel.instrumentation.version>2.15.0-alpha</otel.instrumentation.version>
         <java.version>8</java.version>
         <jacoco.line-coverage>0.70</jacoco.line-coverage>
         <checkstyle.skip>false</checkstyle.skip>