update demo link

index.html

@@ -166,7 +166,8 @@
         </span>
 
         <span class="link-block">
-          <a href="https://huggingface.co/spaces/pinyuchen/attention-tracker" class="external-link button is-normal is-rounded is-dark">
+          <a href="https://huggingface.co/spaces/pinyuchen/attention-tracker" target="_blank"
+          class="external-link button is-normal is-rounded is-dark">
             <span class="icon">
               <i class="fas fa-laptop"></i>
             </span>