Active samples use latest version and docs point to latest samples

[onobc]

1. Make sure the active samples are using the latest version of libs (boot, cloud, scdf, etc..).

2. Make sure the docs are all pointing to the latest version of published samples

   • SCDF ref guide (https://docs.spring.io/spring-cloud-dataflow/docs/current/reference/htmlsingle/)
   • Microsite (https://dataflow.spring.io/docs/)