Ignore `/dev/ttyACM` when detecting Raspbee (#274)

* Ignore `/dev/ttyACM` when detecting Raspbee

* Add a test

Improved network reset, attempt 2 (#273)

* Write intentionally invalid network settings when resetting

* Fix unit tests

* Do not wait for CONNECTED state when resetting

Ensure network reset and new network formation works on old firmwares (…

…#272)

Ensure network reset and new network formation works even on old firmwares

Allow backup to complete on old FW versions (#268)

* Allow backup to complete on old FW versions

* Fix unit test

Drop the zigpy `Requests` class (#267)

* Drop the zigpy `Requests` class

* Fix unit tests

* Pass kwargs through

Disable retries for requests, deferring to zigpy (#264)

* Disable retries for requests, deferring to zigpy

* Remove unnecessary unit test

Fail adapter migration if the frame counter cannot be written (#263)

Cleanly shut down the serial port on disconnect (#259)

* Cleanly shut down the serial port on disconnect

* Send `connection_lost` even if we do not have an open serial connection

* Call `super().close()` in `SerialProtocol`

* Use `self._transport.write` instead of `send_data`

* Let zigpy handle flow control

* Bump minimum zigpy version

* Fix unit tests

* Make `api` an async fixture to grab reference to loop early

* Set default pytest-asyncio fixture loop scope

* Fix unit test failing due to event loop caching issue in pytest-asyncio

* Bring test coverage up

Support zigpy packet priority (#262)

* Support zigpy packet priority

* Don't use Python 3.8 in CI

Do not convert `config` multiple times (#260)