Provide full example for the current version of Spring Boot

[ccleve]

As of today, the current version of Spring Boot is 2.4.5. There are no sample applications that show how to make this project work with Junit 5 and the current testing style (@SpringBootTest, etc.).

There are Junit5 snippets in the documentation for this project, but they lack import statements and need some surgery to get them to work.

Just do a simple, working application that tests a Rest endpoint and generates API documentation.

[wilkinsona]

There's a JUnit-5 based sample that's linked from the reference documentation. It uses @SpringBootTest and works as-is when upgraded to Spring Boot 2.4.5.

I've opened #723 to upgrade all of the Spring Boot-based samples to use 2.4.5, but I can't see a need for a new sample. Thanks anyway for the suggestion.