release automation: use changelog bundle amend feature to better describe upstream dependencies

[SylvainJuge]

The upstream dependencies description in the changelog bundle is getting removed by #1237 , the bundle description can't be easily modified with the new approach.

When we'll have such feature available in docs-builder, we should use it to enhance our release notes to provide the upstream dependencies version as we currently have up to 1.12.0 release in https://www.elastic.co/docs/release-notes/edot/sdks/java

[lcawl]

I've created a fix in elastic/docs-builder#4125. It's been merged and should be in the next docs-builder release. If it's not covering all of your use case, please just lmk