Update number.py, fixing depreciated method NumberEntity

Fixes #56
Issue: ButtonPlusBrightness is overriding depreciated methods of an instance of NumberEntity

custom_components/button_plus/number.py

@@ -102,7 +102,7 @@ def device_info(self) -> DeviceInfo:
             identifiers=identifiers,
         )
 
-    async def async_set_value(self, value: float) -> None:
+    async def async_set_native_value(self, value: float) -> None:
         """Set the text value and publish to mqtt."""
         label_topic = f"buttonplus/{self._hub_id}/brightness/{self._brightness_type}"
         _LOGGER.debug(f"ButtonPlus brightness update for {self.entity_id}")