Update announcement.html

Author: thinh-vu

docs/docs/material/overrides/announcement.html

@@ -1,7 +1,7 @@
 {% block announce %} -->
 <!-- Add a panorama banner here -->
 <div style="width: 100%; overflow: hidden; position: relative;">
-  <a href="https://docs.vnstock.site/changes_log/#23-1-2024" style="display: block; width: 100%; height: 100%;">
+  <a href="https://vnstocks.com/docs/tai-lieu/migration-chuyen-doi-sang-vnstock3?utm_source=vnstock-legacy&utm_medium=announcement_bar" style="display: block; width: 100%; height: 100%;">
       <img src="https://docs.vnstock.site/assets/images/vnstock3-migration-notice.png?raw=true" alt="Thông báo quan trọng" style="width: 100%; height: 100%; object-fit: cover;">
   </a>
 </div>