Add git repo deprecation notice

README.md

@@ -2,6 +2,10 @@
 
 Markdown source repo for https://vcvrack.com/manual/
 
+**As of 2021-10-09, this git repo is no longer updated.**
+The VCV Manual has been integrated into the main vcvrack.com web app backend.
+Contact [VCV Support](https://vcvrack.com/support) for suggestions and fixes to this manual.
+
 ## License
 
 All documentation text in this repository is licensed under [CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0/).