forked from firka/flutter
- rename `kGray8 --> kFlutterSoftwarePixelFormatGray8` - rename `kRGB565 --> kFlutterSoftwarePixelFormatRGB565` - etc.
- rename `kGray8 --> kFlutterSoftwarePixelFormatGray8` - rename `kRGB565 --> kFlutterSoftwarePixelFormatRGB565` - etc.