Support CRD plural name checking in crddiff

[ulucinar]

What problem are you facing?

In a recent issue, the plural names of some resources have changed and this resulted in broken upgrades from the previous versions of the provider. With the current state of our tooling and architecture, we cannot properly handle such changes without requiring some manual intervention.

How could Uptest help solve your problem?

It would be wise to extend crddiff to report such changes in a blocking mode up until we evolve our tooling to be able to cope with such changes. crddiff already has the previous & current versions of a CRD in its context and thus we can extend crddiff to check for plural name changes in addition to the spec.forProvider & status.atProvider breaking API checks (currently acting as a non-blocking linter for these checks).