Bump io.opentelemetry:opentelemetry-bom-alpha

Bumps [io.opentelemetry:opentelemetry-bom-alpha](https://github.com/open-telemetry/opentelemetry-java) from 1.30.1-alpha to 1.31.0-alpha.
- [Release notes](https://github.com/open-telemetry/opentelemetry-java/releases)
- [Changelog](https://github.com/open-telemetry/opentelemetry-java/blob/main/CHANGELOG.md)
- [Commits](https://github.com/open-telemetry/opentelemetry-java/commits)

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

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

getting-started-guides/java/instrumented/build.gradle

@@ -20,7 +20,7 @@ dependencies {
 
   // OpenTelemetry core
   implementation platform('io.opentelemetry:opentelemetry-bom:1.30.1')
-  implementation platform('io.opentelemetry:opentelemetry-bom-alpha:1.30.1-alpha')
+  implementation platform('io.opentelemetry:opentelemetry-bom-alpha:1.31.0-alpha')
   implementation 'io.opentelemetry:opentelemetry-api'
   implementation 'io.opentelemetry:opentelemetry-sdk'
   implementation 'io.opentelemetry:opentelemetry-exporter-otlp'