Elastic OTel Java breaking changes

Breaking changes can impact your applications, potentially disrupting normal operations and their monitoring. Before you upgrade, carefully review the Elastic OTel Java breaking changes and take the necessary steps to mitigate any issues.

1.9.0

Document universal profiling as opt-in. #958

1.6.0

This release is based on the following upstream versions:

opentelemetry-java-instrumentation: 2.20.1
opentelemetry-java: 1.54.1
semantic-conventions-java: 1.37.0
opentelemetry-java-contrib: 1.49.0
Switch to 2.18.1, and switch openai to upstream. #763