Update README.md

Added notice about archiving this repo.

Author: adam-coster

README.md

@@ -1,3 +1,5 @@
+**⚠️ These packages have been migrated into the [Stitch monorepo](https://github.com/bscotch/stitch). This repo is archived for historical purposes.**
+
 # GameMaker Info
 
 Repository of knowledge and data about the [GameMaker engine](https://gamemaker.io/).
@@ -10,4 +12,4 @@ Repository of knowledge and data about the [GameMaker engine](https://gamemaker.
 
 ## Related Projects
 
-+ **[Stitch](https://www.npmjs.com/package/@bscotch/stitch):** A toolkit for automated management of GameMaker projects, including batching sound and sprite asset creation/updates.
++ **[Stitch](https://www.npmjs.com/package/@bscotch/stitch):** A toolkit for automated management of GameMaker projects, including batching sound and sprite asset creation/updates.