Improve changelog by pointing out breaking changes
### Changed
- Dont set log level for root logger (#767) 8/28/20 df81b168
+- Uvicorn no longer ships extra dependencies `uvloop`, `websockets` and
+ `httptools` as default. To install these dependencies use
+ `uvicorn[standard]`.
### Fixed
- Revert "Improve shutdown robustness when using `--reload` or multiprocessing (#620)" (#756) 8/28/20 ff4af12d
