[DOCS] Adds Release Notes for 8.5.2

Author: picandocodigo

CHANGELOG.md

@@ -1,5 +1,12 @@
 *To see release notes for the `7.x` branch and older releases, see [CHANGELOG on the 7.17 branch](https://github.com/elastic/elasticsearch-ruby/blob/7.17/CHANGELOG.md).*
 
+## 8.5.2 Release notes
+
+### API Bugfix
+
+Fixes `security.create_service_token` API, uses `POST` when token name isn't present.
+Thanks [@carlosdelest](https://github.com/carlosdelest) for reporting in [#1961](https://github.com/elastic/elasticsearch-ruby/pull/1961).
+
 ## 8.5.1 Release notes
 
 ### Bugfix

docs/release_notes/85.asciidoc

@@ -1,6 +1,16 @@
 [[release_notes_85]]
 === 8.5 Release notes
 
+[discrete]
+[[release_notes_852]]
+=== 8.5.2 Release notes
+
+[discrete]
+==== API Bugfix
+
+Fixes `security.create_service_token` API, uses `POST` when token name isn't present.
+Thanks https://github.com/carlosdelest[@carlosdelest] for reporting in https://github.com/elastic/elasticsearch-ruby/pull/1961[#1961].
+
 [discrete]
 [[release_notes_851]]
 === 8.5.1 Release notes