Update CHANGELOG.md

Author: oleibman

CHANGELOG.md

@@ -29,6 +29,7 @@ and this project adheres to [Semantic Versioning](https://semver.org).
 - Xlsx Writer Duplicate ContentTypes Entry for Background Image. [Issue #4179](https://github.com/PHPOffice/PhpSpreadsheet/issues/4179) [PR #4180](https://github.com/PHPOffice/PhpSpreadsheet/pull/4180)
 - Check strictNullComparison outside of loops. [PR #3347](https://github.com/PHPOffice/PhpSpreadsheet/pull/3347)
 - SUMIFS Does Not Require xlfn. [Issue #4182](https://github.com/PHPOffice/PhpSpreadsheet/issues/4182) [PR #4186](https://github.com/PHPOffice/PhpSpreadsheet/pull/4186)
+- Image Transparency/Opacity with Html Reader Changes. [Discussion #4117](https://github.com/PHPOffice/PhpSpreadsheet/discussions/4117) [PR #4142](https://github.com/PHPOffice/PhpSpreadsheet/pull/4142)
 
 ## 2024-09-29 - 3.3.0 (no 3.0.\*, 3.1.\*, 3.2.\*)