release_notes: update with Python ALPN fix
@@ -19,3 +19,7 @@ This file tracks release notes for the loop client.
#### Breaking Changes
#### Bug Fixes
+- Certain versions of the Python gRPC library
+ [weren't able to connect](https://github.com/grpc/grpc/issues/23172) to
+ `loopd`'s gRPC interface, getting the `missing selected ALPN property` error.
+ A server side fix was introduced to get rid of that error message.
