docs: add proposed archive notice

Author: ShingZhanho

README.md

@@ -1,3 +1,7 @@
+> [!warning]
+> This repository will be archived soon. All resources will be migrated to a new repository
+> for managing all course materials in a more systematic approach.
+
 # COMP2120 Notes
 
 ## Revision Notes
@@ -33,4 +37,4 @@ without the written permission of the author and the author(s) of the textbook.
 
 The author(s) of the textbook shall not be held responsible for any errors or omissions
 in the notes. Opinions and views expressed in the notes are solely the author's and
-do not represent the views of the author(s) of the textbook.
+do not represent the views of the author(s) of the textbook.