eclipse-mosquitto: Minor doc tweaks, plus *square* logo

eclipse-mosquitto/README-short.txt

@@ -1 +1 @@
-Eclipse Mosquitto is an open source message broker which implements MQTT version 3.1 and 3.1.1
+Eclipse Mosquitto is an open source message broker which implements MQTT version 5, 3.1.1 and 3.1

eclipse-mosquitto/content.md

@@ -1,6 +1,6 @@
 # What is Eclipse Mosquitto?
 
-Eclipse Mosquitto is an open source implementation of a server for version 3.1 and 3.1.1 of the MQTT protocol. Main homepage: http://mosquitto.org/
+Eclipse Mosquitto is an open source implementation of a server for versions 5, 3.1.1, and 3.1 of the MQTT protocol. Main homepages: http://mosquitto.org/
 
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