Update AmbientLightManager.java

fix 设置错误参数，将明亮的值设置成黑暗的值

lib/src/main/java/com/king/zxing/AmbientLightManager.java

@@ -104,7 +104,7 @@ public class AmbientLightManager implements SensorEventListener {
      * @param lightLux
      */
     public void setBrightLightLux(float lightLux){
-        this.darkLightLux = lightLux;
+        this.brightLightLux = lightLux;
     }
 
     @Override
@@ -148,4 +148,4 @@ public class AmbientLightManager implements SensorEventListener {
          */
         void onSensorChanged(boolean dark,float lightLux);
     }
-}
+}