Update docs.

Build/MQTTnet.nuspec

@@ -2,7 +2,7 @@
 <package >
   <metadata>
     <id>MQTTnet</id>
-    <version>2.7.1</version>
+    <version>2.7.2</version>
     <authors>Christian Kratky</authors>
     <owners>Christian Kratky</owners>
     <licenseUrl>https://github.com/chkr1011/MQTTnet/blob/master/LICENSE</licenseUrl>
@@ -10,15 +10,11 @@
     <iconUrl>https://raw.githubusercontent.com/chkr1011/MQTTnet/master/Images/Logo_128x128.png</iconUrl>
     <requireLicenseAcceptance>false</requireLicenseAcceptance>
     <description>MQTTnet is a high performance .NET library for MQTT based communication. It provides a MQTT client and a MQTT server (broker).</description>
-    <releaseNotes>* [Core] Fixed wrong parsing of ConnAck packet for protocol version 3.1.0.
-* [Core] Log messages are now overriding ToString() and providing a ready to use text representation.
-* [Client] Optimized package dispatcher and added several new exceptions.
-* [Client] The _ManagedClient_ now has an event which is fired after a queued application message was processed (including exception).
-* [Client] The _ManagedClient_ now supports unsubscribing (thanks to @lerppana)
-* [Server] Fixed some minor async issues.
-* [Server] Fixed wrong comparison of the topic and QoS for retained messages.
-* [Server] Added a property which provides access to the used options (read only).
-* [Server] Fixed a null ref expection when using an interceptor and publishing via the server directly.
+    <releaseNotes>* [Client] Added the subprotocol "mqtt" as default for web socket based connections.
+* [Client] Added a new client setting called "KeepAliveSendInterval". It allows configuring the effective interval for sending ping requests.
+* [Client] The client will no longer send ping requests if other packets are sent within the configured interval.
+* [Server] The server now generates a valid packet identifier when disaptching publish packets to clients.
+* [Core] Add several new extension methods.
     </releaseNotes>
     <copyright>Copyright Christian Kratky 2016-2018</copyright>
     <tags>MQTT Message Queue Telemetry Transport MQTTClient MQTTServer Server MQTTBroker Broker NETStandard IoT InternetOfThings Messaging Hardware Arduino Sensor Actuator M2M ESP Smart Home Cities Automation Xamarin</tags>