This is the second alpha release of the "modern" 3.0 branch.
The main improvements in this version are:
* Fix some issues with Hasura backend:
* optional variables an operation name for aiohttp and websockets transports (94)
* ignoring keep-alive messages arriving before the connection_ack message (110)
* Using more specific exceptions (95)
* It is now possible to get all the returned errors in the TransportQueryError exception (96)
* Documentation: Improved README.md and added coding guidelines to CONTRIBUTING.md (97 114)
* 100% tests coverage (107)
* Graceful shutdown for synchronous subscriptions (99)
* type_def argument in Client is now deprecated in favor of schema (113)