Log Message:
py-daphne: updated to 2.4.0

2.4.0:
* Adds CI testing against and support for Python 3.8.
* Adds support for ``raw_path`` in ASGI scope.
* Ensures an error response is sent to the client if the application sends
  malformed headers.
* Resolves an asyncio + multiprocessing problem when testing that would cause
  the test suite to fail/hang on macOS.
* Requires installing Twisted's TLS extras, via ``install_requires``.
* Adds missing LICENSE to distribution.