chore: add note about rename

Author: gadomski

CHANGELOG.md

@@ -7,6 +7,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 
 ## [0.6.0] - 2025-04-18
 
+> [!NOTE]
+> This package was renamed from **stacrs** to **rustac**.
+
 ### Added
 
 - Construct `stac_api::Search` (moved from `stac_api` crate) ([#81](https://github.com/stac-utils/rustac-py/pull/81))