updated onEvent example implementation to follow better coding practices

Author: Jorge Diaz Alvarado

packages/@aws-cdk/example-construct-library/lib/example-resource.ts

@@ -201,7 +201,11 @@ abstract class ExampleResourceBase extends Resource implements IExampleResource
    * as it simplifies the implementation code (less branching).
    */
   public onEvent(id: string, options: events.OnEventOptions = {}): events.Rule {
-    const rule = new events.Rule(this, id, options);
+    const rule = new events.Rule(this, id, {
+      description: options.description,
+      ruleName: options.ruleName,
+      crossStackScope: options.crossStackScope,
+    });
     rule.addTarget(options.target);
     rule.addEventPattern({
       // obviously, you would put your resource-specific values here