add banner

Author: rlanzafame

book/_config.yml

@@ -36,7 +36,7 @@ html:
   use_repository_button: true
   use_edit_page_button: true
   use_multitoc_numbering: false
-  # announcement: "⚠️ This is not the final version of the book! The new version will be ready by July 1.⚠️"
+  announcement: "<p>This book was recently updated for the 2025-26 academic year. The previous version of the book can be found at <a href='https://teachbooks.nl/learn-python/2024' style='color: cyan;'>teachbooks.nl/learn-python/2024</a></p>"
   extra_navbar: |
       <div>
           <IMG SRC="https://raw.githubusercontent.com/mbakker7/exploratory_computing_with_python/master/tudelft_logo.png" WIDTH=200 ALIGN="center">