* [MQTTnet.Server] Added interceptor for unsubscriptions.
* [MQTTnet.AspNetCore] improved compatibility with AspNetCore 3.1
* [Core] Added MqttApplicationMessage.GetUserProperty() convenience method (thanks to @PMExtra).
* [Client] Support WithConnectionUri to configure client (thanks to @PMExtra).
* [Server] Removed exceptions when user properties are set with MQTT protocol version 3.1
* [LowLevelMqttClient] Added low level MQTT client in order to provide more flexibility when using the MQTT protocol. This client requires detailed knowledge about the MQTT protocol.
</releaseNotes>
<copyright>Copyright Christian Kratky 2016-2020</copyright>