📝 Update release notes

[skip ci]

docs/en/docs/release-notes.md

@@ -38,6 +38,7 @@ hide:
 
 ### Internal
 
+* ⚡️ Speed up test suite via caching and fixture scopes to make it ~24% faster. PR [#13583](https://github.com/fastapi/fastapi/pull/13583) by [@dikos1337](https://github.com/dikos1337).
 * 🔥 Remove config files now in central GitHub repo. PR [#15585](https://github.com/fastapi/fastapi/pull/15585) by [@tiangolo](https://github.com/tiangolo).
 * ⬆ Bump urllib3 from 2.6.3 to 2.7.0. PR [#15502](https://github.com/fastapi/fastapi/pull/15502) by [@dependabot[bot]](https://github.com/apps/dependabot).
 * ⬆ Bump idna from 3.11 to 3.15. PR [#15565](https://github.com/fastapi/fastapi/pull/15565) by [@dependabot[bot]](https://github.com/apps/dependabot).