fix(demo): allow opening PSD files on Windows

Due to inconsistencies in how browsers across different platforms handle
the `accept` field of a file input, we need to use file extensions,
rather than MIME types, to allow opening PSD files.

examples/browser/statics/index.html

@@ -74,7 +74,7 @@ <h2>Features</h2>
     <section>
       <div class="section-content">
         <h2>Select psd/psb file</h2>
-        <input type="file" accept="image/vnd.adobe.photoshop,.psb" />
+        <input type="file" accept=".psd,.psb" />
         <h2>Results</h2>
         <p>
           After the file is selected, the PSD file parsing result is shown