docs(readme): add "early development" section

README.md

@@ -2,6 +2,8 @@
 
 A **jsx-free**, **super-lightweight** and **zero-dependency** library to add reactivity to the web — without all the nonsense.
 
+> ! Tent is currently in early development. It _can_ be used in production, but there might be breaking changes. If you're interested in contributing, please submit a PR or report an issue. Keep track of the changes in the [CHANGELOG](CHANGELOG.md).
+
 ## ⚙️ Installation
 
 ```bash