docs: update changelog for integrations/pgvector (#1997)

* Update changelog for integrations/pgvector

* Update CHANGELOG.md

---------

Co-authored-by: anakin87 <44616784+anakin87@users.noreply.github.com>
Co-authored-by: Stefano Fiorucci <stefanofiorucci@gmail.com>

Author: HaystackBot

integrations/pgvector/CHANGELOG.md

@@ -1,5 +1,15 @@
 # Changelog
 
+## [integrations/pgvector-v5.2.0] - 2025-06-26
+
+Note: Version 5.2.0 was released by mistake.
+It is functionally identical to version 3.4.1 and does not introduce any new features or changes.
+
+### 🧹 Chores
+
+- Remove black (#1985)
+
+
 ## [integrations/pgvector-v3.4.1] - 2025-06-20
 
 ### 🐛 Bug Fixes