Added the DNG file into the MAC OS sample

samples/Skia.OSX.Demo/Skia.OSX.Demo.csproj

@@ -108,6 +108,9 @@
     <EmbeddedResource Include="..\SharedDemo\color-wheel.png">
       <Link>color-wheel.png</Link>
     </EmbeddedResource>
+    <EmbeddedResource Include="..\SharedDemo\adobe-dng.dng">
+      <Link>adobe-dng.dng</Link>
+    </EmbeddedResource>
   </ItemGroup>
   <ItemGroup>
     <BundleResource Include="..\SharedDemo\content-font.ttf">