Add a 'status' to README

Signed-off-by: Greg Haskins <[email protected]>

Author: ghaskins

README.md

@@ -7,6 +7,9 @@ resilient applications using developer-friendly primitives, instead of constantl
 
 This Clojure SDK is a framework for authoring Workflows and Activities in Clojure. (For other languages, see [Temporal SDKs](https://docs.temporal.io/application-development).)
 
+### Status
+
+**Alpha**: Functional, but undergoing active development.  Some major features (Queries, Child-Workflows, SideEffects, etc) are missing/imcomplete.  API may evolve in breaking ways, though we will always bump at least the minor version when this happens and include a note.
 ### Clojure SDK
 
 - [Clojure SDK and API documentation](https://cljdoc.org/d/io.github.manetu/temporal-sdk)