[295] Usage should say we support 3.1.1 as well as 3.1.

Closes #295.

Bug: https://github.com/eclipse/mosquitto/issues/295

src/conf.c

@@ -309,7 +309,7 @@ void mqtt3_config_cleanup(struct mqtt3_config *config)
 static void print_usage(void)
 {
 	printf("mosquitto version %s (build date %s)\n\n", VERSION, TIMESTAMP);
-	printf("mosquitto is an MQTT v3.1 broker.\n\n");
+	printf("mosquitto is an MQTT v3.1.1/v3.1 broker.\n\n");
 	printf("Usage: mosquitto [-c config_file] [-d] [-h] [-p port]\n\n");
 	printf(" -c : specify the broker config file.\n");
 	printf(" -d : put the broker into the background after starting.\n");