Update changelog

Author: jsignell

CHANGELOG.md

@@ -2,11 +2,17 @@
 
 ## [Unreleased]
 
+
+### Added
+
+- Top-level `item_assets` dict on `Collection`s ([#1476](https://github.com/stac-utils/pystac/pull/1476))
+
 ### Changed
 
 - Write STAC v1.1.0 ([#1427](https://github.com/stac-utils/pystac/pull/1427))
 - Use [uv](https://github.com/astral-sh/uv) for development dependencies and docs ([#1439](https://github.com/stac-utils/pystac/pull/1439))
 - Correctly detect absolute file path ref on windows, reflecting change in python 3.13 ([#1475](https://github.com/stac-utils/pystac/pull/14750)) (only effects python 3.13)
+- Deprecated `ItemAssetExtension` ([#1476](https://github.com/stac-utils/pystac/pull/1476))
 
 ## [v1.11.0] - 2024-09-26