Add CHANGES entry for #424

Author: duckontheweb

CHANGES.md

@@ -32,6 +32,7 @@
 * Fixed stray `/` before the `#` in several extension conformance class strings ([383](https://github.com/stac-utils/stac-fastapi/pull/383))
 * SQLAlchemy backend bulk item insert now works ([#356](https://github.com/stac-utils/stac-fastapi/issues/356))
 * PGStac Backend has stricter implementation of Fields Extension syntax ([#397](https://github.com/stac-utils/stac-fastapi/pull/397))
+* PGStac Backend Transactions endpoints return added Item/Collection instead of Item/Collection from request ([#424](https://github.com/stac-utils/stac-fastapi/pull/424))
 
 ## [2.3.0]