Bump io.opentelemetry:opentelemetry-bom-alpha in /java (#733)

Bumps [io.opentelemetry:opentelemetry-bom-alpha](https://github.com/open-telemetry/opentelemetry-java) from 1.29.0-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]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

Author: dependabot[bot]

java/build.gradle.kts

@@ -29,7 +29,7 @@ val javaagentDependency by configurations.creating {
 
 dependencies {
     compileOnly(platform("io.opentelemetry:opentelemetry-bom:1.30.0"))
-    compileOnly(platform("io.opentelemetry:opentelemetry-bom-alpha:1.30.0-alpha"))
+    compileOnly(platform("io.opentelemetry:opentelemetry-bom-alpha:1.31.0-alpha"))
     // Already included in wrapper so compileOnly
     compileOnly("io.opentelemetry:opentelemetry-sdk-extension-autoconfigure-spi")
     compileOnly("io.opentelemetry:opentelemetry-sdk-extension-aws")