BAEL3236 Fixing test cases and updating the missed version in pom.xml

ratpack/src/main/java/com/baeldung/handler/FooHandler.java

@@ -0,0 +1,12 @@
+package com.baeldung.handler;
+
+import ratpack.handling.Context;
+import ratpack.handling.Handler;
+
+public class FooHandler implements Handler {
+    @Override
+    public void handle(Context ctx) throws Exception {
+        ctx.getResponse()
+            .send("Hello Foo!");
+    }
+}