Revert "unpin template"

This reverts commit 2a23803.

Author: jo-mueller

myst.yml

@@ -113,4 +113,6 @@ site:
   parts:
     footer: footer.md
 
-  template: book-theme
+  # Temporarily hash-pin the theme.
+  # See: https://github.com/jupytercon/jupytercon2025-developingextensions/issues/6
+  template: "https://github.com/myst-templates/book-theme/archive/de4c1e9c09c6cd12fc529c1f22e8abf8e7f35381.zip"