Update README.md to redirect users to a maintained fork

Author: btry

README.md

@@ -7,6 +7,8 @@
 [![Project Status: Active](http://www.repostatus.org/badges/latest/active.svg)](http://www.repostatus.org/#active)
 [![Conventional Commits](https://img.shields.io/badge/Conventional%20Commits-1.0.0-yellow.svg)](https://conventionalcommits.org)
 
+:warning: This repository has been archived. A [fork of this repository](https://github.com/moodlehq/CFPropertyList/) has beeen created by the organization Moodlehq on Github to continue its maintenance. Please use it instead.
+
 Teclib’ is an open source software editor that offers a vast range of fully integrated open source technology packages, to better respond to business needs.
 
 Visit our Website [Teclib'](http://www.teclib-edition.com/en/).
@@ -63,4 +65,4 @@ guidelines for [contributing](./CONTRIBUTING.md) and then check out one of our i
 
 * **Code**: you can redistribute it and/or modify
     it under the terms of the MIT License ([MIT](https://opensource.org/licenses/MIT)).
-* **Documentation**: released under Attribution 4.0 International ([CC BY 4.0](https://creativecommons.org/licenses/by/4.0/)).
+* **Documentation**: released under Attribution 4.0 International ([CC BY 4.0](https://creativecommons.org/licenses/by/4.0/)).