- Added `on_connect` and `on_disconnect` options to `ariadne.asgi.GraphQL`, enabling developers to run additional initialization and cleanup for websocket connections.
- Updated Starlette dependency to 0.17.1.
- Added support for multiple keys for GraphQL federations.
- Made `Query` type optional in federated schemas.
- Updated default resolvers to test for `Mapping` instead of `dict`.
- Removed `ariadne.contrib.django`. (Use [ariadne_django](https://github.com/reset-button/ariadne_django) instead).
- Updated query cost validator to handle optional variables.