Fix gas resistance reading

There is a report in the M5Stack community forum that ENVPro unit fails to report gas resistance. Apparently the returned number alwas is 0.0. So I looked into the source code and it looks like there might be a copy paste error here.

Please note: I do not have the ENVPro unit myself so I cannot test this. It's just a hunch that this might be the issue.

Author: felmue

m5stack/libs/driver/bme68x.py

@@ -560,7 +560,7 @@ def _read_field_data(self, index) -> BME68xData:
             if self._variant_id == 0x01:
                 gas_resistance = self.calc_gas_resistance_high(adc_gas_res_high, gas_range_h)
             else:
-                gas_resistance = self.calc_gas_resistance_high(adc_gas_res_low, gas_range_l)
+                gas_resistance = self.calc_gas_resistance_low(adc_gas_res_low, gas_range_l)
 
             self._sensor_data[0].status = status
             self._sensor_data[0].gas_index = gas_index