Most projects start out with an alpha API that changes release to release. However, eventually, most projects will need to move to a more stable API. Once your API is stable though, you can't make breaking changes to it. That's where API versions come into play.
Let's make some changes to the CronJob API spec and make sure all the
different versions are supported by our CronJob project.
If you haven't already, make sure you've gone through the base CronJob Tutorial.
Note that most of this tutorial is generated from literate Go files that form a runnable project, and live in the book source directory: docs/book/src/multiversion-tutorial/testdata/project.
Next, let's figure out what changes we want to make...