Support for strict / non-strict validation

[yannh]

An interesting discussion started over here: yannh/kubeconform#171
A user is pointing out (correctly I believe) that we don't really make the distinction for strict vs non-strict validation for CRDs, whereas kubernetes-json-schema has schemas for both "strict" and "non-strict" mode. The strict schemas will complain when keys are used in the resource that are not present in the schema, vs the non-strict mode will not count this as an error.

In the user's case, they use a self-generated json schema, but I was wondering what the viewpoint was here - whether CRDs-catalog should also provide a strict and non-strict JSON schema for each CRD, or what the default really should be (I would be tempted to say, default to strict?).

Best,
Yann

[eyarz]

To be frank, we didn't consider this when we started this project.
we are using the schema that is generated by default via the openapi2jsonschema.py script, and it looks like those are not strict.

I don't see any reason why not to address this issue, so if the community would like to submit PRs we will accept them :)