Document updating test data

[chrislovecnm]

If you set this to true

cockroach-operator/pkg/resource/statefulset_test.go

Line 39 in bb9aeaf

var update = flag.Bool("update", false, "update the golden files of this test")

The run bazel test //pkg/... it will update all of the test data for you.

We have other places where this is utilized as well. It is recommended to not update the test data by hand, but review the changes.

[johnrk-zz]

@keith-mcclellan says that this is developer docs.

[johnrk-zz]

@taroface , this is something we would probably work on after our initial release.

[jreut]

Howdy! Is there a reason I'm assigned to this issue? What exactly needs to be done here?