Deprecation warnings

[newAM]

Assigning myself, just wanted to create an issue to track existing deprecation warnings.

pycec/network.py:173
  /home/alex/git/pyCEC/pycec/network.py:173: DeprecationWarning: "@coroutine" decorator is deprecated since Python 3.8, use "async def" instead
    def async_turn_on(self):  # pragma: no cover

3 things need to change to update the syntax:

• Remove loop argument in functions
• Change coroutine decorated functions to async def
• Change yield from to await