Add unique-ids to maxcube component (#49196)

homeassistant/components/maxcube/binary_sensor.py

@@ -35,6 +35,11 @@ class MaxCubeShutter(BinarySensorEntity):
         """Return the name of the BinarySensorEntity."""
         return self._name
 
+    @property
+    def unique_id(self):
+        """Return a unique ID."""
+        return self._device.serial
+
     @property
     def device_class(self):
         """Return the class of this sensor."""