Add release 4.15.2 release note (#3500)
Add release 4.15.2 release note (#3500)

* Add release 4.15.2 release note
---

*Motivation*

Generates the 4.15.2 release note

* Update site3/website/src/pages/release-notes.md
apache/bookkeeper,apache/bookkeeper,apache/bookkeeper,apache/bookkeeper,apache/bookkeeper,apache/bookkeeper