textScaleFactory 改为 textScaleFactor , 去掉多余的y

lib/flutter_screenutil.dart

@@ -52,7 +52,7 @@ class ScreenUtil {
 
   /// 每个逻辑像素的字体像素数，字体的缩放比例
   /// The number of font pixels for each logical pixel.
-  static double get textScaleFactory => _textScaleFactor;
+  static double get textScaleFactor => _textScaleFactor;
 
   /// 设备的像素密度
   /// The size of the media in logical pixels (e.g, the size of the screen).