Add disclaimer to readme about 0.5

README.md

@@ -52,6 +52,10 @@
 
 <br/>
 
+> [!WARNING]
+> Dioxus 0.5 (currently in master) contains massive breaking changes and is not compatible with Dioxus 0.4
+> The current version of docs and published crates is for Dioxus 0.4 - the docs for 0.5 are not yet complete.
+
 Dioxus is a portable, performant, and ergonomic framework for building cross-platform user interfaces in Rust.
 
 ```rust