Discover USB ports only

This will ignore f.ex. bluetooth

main.go

@@ -714,8 +714,10 @@ func getDefaultPort(portCandidates []string) (port string, err error) {
 		}
 
 		for _, p := range portsList {
+			if p.IsUSB {
 				ports = append(ports, p.Name)
 			}
+		}
 
 		if ports == nil || len(ports) == 0 {
 			// fallback