add banner

Author: rlanzafame

book/_config.yml

@@ -35,7 +35,7 @@ html:
   use_issues_button: true
   use_repository_button: true
   use_edit_page_button: true
-  # announcement: "⚠️ This is not the final version of the book! The new version will be ready by July 1.⚠️"
+  announcement: "<p>This version of the book is from the 2024-25 academic year and earlier. A new version of this book can be found at <a href='https://teachbooks.nl/learn-python' style='color: cyan;'>teachbooks.nl/learn-python</a></p>"
   extra_navbar: |
       <div>
           <IMG SRC="https://raw.githubusercontent.com/mbakker7/exploratory_computing_with_python/master/tudelft_logo.png" WIDTH=200 ALIGN="center">