feat: add Google Colab badge

assets/title.html

@@ -22,5 +22,9 @@
             <a href="https://github.com/CK-Explorer/DuoSubs/blob/main/LICENSE" target="_blank">
             <img class="hover-badge" src="https://img.shields.io/badge/license-Apache--2.0-blueviolet.svg" />
         </a>
+        </a>
+            <a href="https://colab.research.google.com/CK-Explorer/DuoSubs/blob/notebook/DuoSubs-webui.ipynb" target="_blank">
+            <img class="hover-badge" src="https://colab.research.google.com/assets/colab-badge.svg" />
+        </a>
     </div>
 </div>