Point to the JUnit5 examples from the root README

Author: jponge

README.adoc

@@ -148,6 +148,12 @@ your Vert.x (or other asynchronous) applications.
 
 The link:unit-examples/README.adoc[Vert.x Unit examples] shows how to use Vert.x Unit.
 
+=== Vert.x JUnit 5 examples
+
+The `vertx-junit5` modules allows testing Vert.x asynchronous operations with JUnit 5.
+
+See link:junit5-examples/README.adoc[Vert.x JUnit 5 examples].
+
 === RxJava examples
 
 Vert.x for RxJava provides most of its APIs as RxJava so you can use those if you prefer.