Add archival notice to README (#44)

Author: krossgg

README.md

@@ -1,24 +1,6 @@
 # GregTech CEu Modern Documentation
-
-This documentation project is built using [MkDocs](https://www.mkdocs.org/#).
-
-For an automatically updating live preview in your browser, run `mkdocs serve`
-
-
-## Installing Required Dependencies
-
-To install the required dependencies, please run `pip install -r requirements.txt`
-
-
-## Used MkDocs Plugins
-
-The following plugins for MkDocs are being used:
-
-- https://squidfunk.github.io/mkdocs-material/
-- https://github.com/lukasgeiter/mkdocs-awesome-pages-plugin
-
-## Contributing
-
-When contributing to this project, please refer to the [Styleguide](./CONTRIBUTING.md).  
-I know it's kinda long, but it will help in keeping the documentation consistent. You will also find examples of
-when to use specific features of mkdocs and mkdocs-material.
+> [!WARNING]
+> This repository is **no longer being maintained.**
+> Our docs can now be found [here](https://gregtechceu.github.io/GregTech-Modern/).
+> 
+> If you would like to contribute, view the instructions [on our main repository](https://github.com/GregTechCEu/GregTech-Modern/tree/1.20.1/docs)