docs: update changelog

Author: atrigila

CHANGELOG.md

@@ -19,6 +19,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - [PR #1528](https://github.com/nf-core/rnaseq/pull/1528) - Improve JSON schema validation files
 - [PR #1523](https://github.com/nf-core/rnaseq/pull/1523) - Update preprocessing subworkflow to fix linting block on trimming
 - [PR #1521](https://github.com/nf-core/rnaseq/pull/1521) - Updated Perl conda package version for local module gtf2bed for Arm compatibility.
+- [PR #1550](https://github.com/nf-core/rnaseq/pull/1550) - Simplify `SummarizedExperiment` outputs.
 
 # 3.18.0 - 2024-12-19