📝 Update release notes

docs/release-notes.md

@@ -1,5 +1,6 @@
 ## Latest changes
 
+* Fix callback handling for sub-routers. PR [#792](https://github.com/tiangolo/fastapi/pull/792) by [@jekirl](https://github.com/jekirl).
 * Fix typos. PR [#784](https://github.com/tiangolo/fastapi/pull/784) by [@kkinder](https://github.com/kkinder).
 * Add 4 Japanese articles to [External Links](https://fastapi.tiangolo.com/external-links/). PR [#783](https://github.com/tiangolo/fastapi/pull/783) by [@HymanZHAN](https://github.com/HymanZHAN).
 * Add support for subtypes of main types in `jsonable_encoder`, e.g. asyncpg's UUIDs. PR [#756](https://github.com/tiangolo/fastapi/pull/756) by [@RmStorm](https://github.com/RmStorm).