Add bm.benchmark ground-truth alignment fix to changelog (#302)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: PauBadiaM

CHANGELOG.md

@@ -13,6 +13,7 @@ and this project adheres to [Semantic Versioning][].
 ### Bugfixes
 - Fixed `op.translate` (and every `op.resource` call for non-human organisms) failing with HTTP 404 after HGNC dropped the `genenames/` subtree from the EBI FTP mirror; the HCOP fifteen-column files are now fetched from the new HGNC Google Cloud Storage bucket (#303)
 - Removed a redundant `pd.read_csv` call in `op.translate` that re-downloaded the HCOP file a second time and bypassed the retry logic in `_download`
+- Fixed `bm.benchmark` ground-truth matrix row order not matching score matrix after `pivot`, which silently misaligned perturbation labels when obs names sort differently from their original order (#302)
 
 ## 2.1.5