Also updates CI pypy versions to be 3.9 and 3.10 which are the currently
[supported
versions](https://www.pypy.org/posts/2024/01/pypy-v7315-release.html).
Otherwise latest cryptography doesn't ship with pypy3.8 wheels and is
unable to build on windows.
Also updates the `codecov-action` to v4 which fixed some intermittent
uploading errors.
With the move towards autodetecting available features, there is no reason to keep SmartPlug around.
kasa.smart.SmartPlug is removed in favor of kasa.smart.SmartDevice which offers the same functionality.
Information about auto_off can be accessed using Features of the AutoOffModule on supported devices.
Co-authored-by: Steven B. <51370195+sdb9696@users.noreply.github.com>
