Add current_humidity attribute on climate modbus

Feature Requests
1

Climate support current_humidity attribute but It lack on modbus climate entities

To test on my enviroment I modified climate.yaml code adding this code on async_update function and it works fine

self._attr_current_humidity = int(await self._async_read_register(self._input_type, 199) * 10)

I suggest to add it with a scale option (in my case i need to multiply 10 times)

Thanks