Graphql-ws-apollo

==================
- Bump django version

==================
- Bump graphql-ws version in source code

==================
- Removed support for Django 2
- Added GitHub actions
- Added Channels v3 compatibility
- Added new module to support Channels > 1 18
- Fix: tests are running again
- Fix: Correctly unsubscribe after on_start operation is complete
- Breaking changes

==================
- update travis deployment credentials and remove travis autogen config

==================

- Django channels (v1) server (with example app).

- Websockets lib server (with example app).

- Observable aiter server.

==================

- Add gevent subscription server.

- Add example flask gevent app.