update index.html

Author: rainliu

index.html

@@ -134,7 +134,7 @@
             <tr>
               <td style="border: 0"><img src="./res/webrtc_crates_dep_graph.png"></td>
               <td style="border: 0">&nbsp;</td>
-              <td style="border: 0"><br><img src="./res/webrtc_stack.png"></td>
+              <td style="border: 0"><img src="./res/webrtc_stack.png"></td>
             </tr>
         </table>
         <hr>