Putting timestamp in CHANGELOG.org of modus-themes

[irenezerafa]

Am using modus-themes for emacs, and at the end of modus-themes.el, there is 
the following code

(provide 'modus-themes)

;; Local Variables:
;; time-stamp-pattern: "Last-Modified: <%Y-%02m-%02d %02H:%02M:%02S %5z>"
;; End:

;;; modus-themes.el ends here

To insert the timestamp, I put (add-hook 'before-save-hook #'time-stamp) in the 
emacs init file,

But I also need a way to synchronise the timestamp from modus-themes.el into the
CHANGELOG.org. What can I do for the time stamp to be inserted.

I would like to have after the line

#+OPTIONS: ':nil toc:nil num:nil author:nil email:nil

the following

Copyright (C) 2019-2021 Free Software Foundation, Inc.
Author: Protesilaos Stavrou <info@protesilaos.com
URL: https://gitlab.com/protesilaos/modus-themes
Version: 1.6.0
Last-Modified: <2021-11-05 10:36:21 +0200
Package-Requires: ((emacs "27.1"))
Keywords: faces, theme, accessibility