Add live IzzyOnDroid download link

KashCal is now available on IzzyOnDroid F-Droid repo.
Updated download section with working link.

Author: one-kash

index.html

@@ -603,10 +603,10 @@ <h3>GitHub Releases</h3>
                 <h3>F-Droid</h3>
                 <p>Coming soon</p>
             </a>
-            <a href="#" class="download-card" style="opacity: 0.6; pointer-events: none;">
+            <a href="https://apt.izzysoft.de/fdroid/index/apk/org.onekash.kashcal" class="download-card">
                 <div class="download-card-icon">📲</div>
                 <h3>IzzyOnDroid</h3>
-                <p>Coming soon</p>
+                <p>F-Droid compatible repo</p>
             </a>
         </div>
     </section>