use only one method of creating an function pointer

things/DeviceLed.h

@@ -89,7 +89,7 @@ bool DeviceLed::ledColorHandler(String message) {
 
 void DeviceLed::homieRegister() {
   ledNode.subscribe("on", [this](String value) { return ledOnHandler(value); });
-  ledNode.subscribe("color", std::bind(&DeviceLed::ledColorHandler, this, std::placeholders::_1));
+  ledNode.subscribe("color", [this](String value) { return ledColorHandler(value); });
   Homie.registerNode(ledNode);
 }