Fix Spring structured example (#451)

Signed-off-by: Micael Vianna <estrazulas@gmail.com>
Signed-off-by: Micael Estrazulas Vianna <m.vianna@kigroup.de>

Author: mEstrazulas

examples/spring-function/README.md

@@ -29,9 +29,9 @@ It also accepts data in "structured" format:
 ```shell
 curl -v -H'Content-type: application/cloudevents+json' \
     -d '{"data": {"value": "Foo"},
-         "id: 1,
-         "source": "cloud-event-example"
-         "type": "my.application.Foo"
+         "id": "1",
+         "source": "cloud-event-example",
+         "type": "my.application.Foo",
          "specversion": "1.0"}' \
     http://localhost:8080/event
 ```