Add note on k8s version support

J12934 · J12934 · commit 9ced2e114d9f · 2020-03-31T17:38:18.000+02:00
diff --git a/README.md b/README.md
@@ -48,7 +48,7 @@ There is a german article about [Security DevOps – Angreifern (immer) einen Sc
 
 ### Prerequisites
 
-- kubernetes
+- kubernetes (last three mayor releases supported: `1.16`, `1.17` & `1.18`)
 
 ### Deployment
 
