Update index.html

index.html

@@ -110,6 +110,7 @@
     <ul>
       <li><strong>June 1, 2025</strong>: Official announcement</li>
       <li><strong>June 10, 2025</strong>: Release of training data, dev set, phonetizer, baselines</li>
+      <li><strong>June 20, 2025</strong>: Opening Leaderboard</li>
       <li><strong>July 20, 2025</strong>: Registration deadline</li>
       <li><strong>July 24, 2025</strong>: QuranMB test data release</li>
       <li><strong>July 29, 2025</strong>: Test set submission closes</li>
@@ -308,7 +309,7 @@ ID,Labels
 
     <h2>Future Updates</h2>
     <p>
-        Further details on the openset leaderboard submission will be posted on the shared task website (June 15, 2025). Stay tuned!
+        Further details on the open-set leaderboard submission will be posted on the shared task website (June 20, 2025). Stay tuned!
     </p>