Prepare 2.0.3 release

Signed-off-by: Kai Hudalla <[email protected]>

Author: sophokles73

site/homepage/content/release-notes.md

@@ -4,6 +4,15 @@ title = "What is new & noteworthy in Hono?"
 description = "Information about changes in recent Hono releases. Includes new features, fixes, enhancements and API changes."
 +++
 
+## 2.0.3
+
+### Fixes & Enhancements
+
+* A vulnerability in the CoAP adapter has been fixed which could have been exploited by malicious devices causing a
+  denial of service.
+* The MQTT adapter's user guide has been improved to be more specific about the topic names being used for publishing
+  commands to gateway devices.
+ 
 ## 2.0.2
 
 ### Fixes & Enhancements