docs: Add disclaimer to the readme (#4)

README.md

@@ -3,6 +3,9 @@
 ![Experimental](https://img.shields.io/badge/experimental-breaking%20changes%20allowed-yellow)
 ![Alpha](https://img.shields.io/badge/alpha-release-red)
 
+> ⚠️ This repositority is a work-in-progress. Tooling and documentation may be incomplete. ⚠️  
+>                 The Python SDK is under active development and is subject to change.
+
 This repository is intended for OpenFeature contributions which are not included in the [OpenFeature SDK](https://github.com/open-feature/python-sdk).
 
 The project includes: