bleak 2.0.0 on Python PyPI

Added

Added bleak.backends.get_default_backend() and BleakBackend enum for a centralized backend detection.
Added BleakClient().backend_id and BleakScanner().backend_id properties to identify the backend in use.

Use "AcquireNotify" rather than "StartNotify" for Linux backend on supported characteristics
Allow multiple calls to disconnect() on Windows to align behavior over all backends.
Raise new BleakBluetoothNotAvailableError when Bluetooth is not supported, turned off or permission is denied.

Fixed potential race condition causing timeout while connecting in WinRT backend.
Fixed file handle leak in BlueZ backend when D-Bus connection is lost and re-established.
Fixed crash in CoreBluetooth backend if an ObjC delegate callback is called after the asyncio run loop stops.
Fixed possible deadlock when starting scanning on Windows when Bluetooth is turned off.
Fixed "Bluetooth device is turned off" Exception on macOS, when a Bluetooth permission request popup is shown to the user by the OS.