📝 Update release notes

Author: github-actions

docs/release-notes.md

@@ -1,5 +1,6 @@
 ## Latest Changes
 
+* 📝 Clarify testing documentation about checking `stderr`. PR [#335](https://github.com/tiangolo/typer/pull/335) by [@cgabard](https://github.com/cgabard).
 * 🐛 Fix type conversion for `List` and `Tuple` and their internal types. PR [#143](https://github.com/tiangolo/typer/pull/143) by [@hellowhistler](https://github.com/hellowhistler).
 * 🐛 Fix `context_settings` for a Typer app with a single command. PR [#210](https://github.com/tiangolo/typer/pull/210) by [@daddycocoaman](https://github.com/daddycocoaman).
 * ✏ Fix typo in docs for CLI Option autocompletion. PR [#288](https://github.com/tiangolo/typer/pull/288) by [@graue70](https://github.com/graue70).