package/python-daphne: bump version to 2.4.1

Other changes:
  - Use the LICENSE file for the license. This prevents having to change the
    sha256sum on every version bump due to PKG-INFO containing the version
    number.

Signed-off-by: Adam Duskett <Aduskett@gmail.com>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@bootlin.com>