Update footer text and copyright information

Author: fmaussion

_config.yml

@@ -25,12 +25,11 @@ html:
   use_edit_page_button: true
   announcement:
   extra_footer: |
-  <p>
-  These notebooks are licensed under the <a href="https://github.com/OGGM/tutorials/blob/master/LICENSE.txt" target="_blank" rel="noopener noreferrer">BSD-3-Clause License</a>.
-  <br>
-  &copy; Copyright 2014–2026. <a href="https://community.oggm.org/legal.html" target="_blank" rel="noopener noreferrer">Legal & Privacy</a>
-  <br>
-  </p>
+    <p>
+    These notebooks are licensed under a <a href="https://github.com/OGGM/tutorials/blob/master/LICENSE.txt" target="_blank">BSD-3-Clause license</a>.
+    <br>
+    &copy; Copyright 2014-2026 OGGM Contributors. <a href="https://community.oggm.org/legal.html" target="_blank" rel="noopener noreferrer">Legal & Privacy</a>
+    </p>
 sphinx:
   config:
     html_show_copyright: false