Fix the s3_wait empty check example

[akito19]

s3_wait operator shows an example for continue_on_timeout. However, it doesn't work when ${s3.last_object} is found.

+task1:
  s3_wait>: bucket/object
  timeout: 60s
  continue_on_timeout: true
+task2:
  if>: ${s3.last_object}
  _do:
    echo>: "No timeout"

So, update the example in order to pass the task2 even if the operator isn't timed out.

[szyn]

Thank you!