bump SpinAppExecutor CRD version and automate updating CRD versions on release

[michelleN]

I believe this should have been done as part of the v0.2.0 release since there was a change to the SpinAppExecutor CRD and going forward we should outline when and how we should be bumping CRDs.

[endocrimes]

It's very uncommon for additive, non-breaking changes to require apiVersion bumps in kubernetes, and bumping them results in a lot of churn (code, documentation, end user configurations), so I'd like to avoid us bumping them in cases where we wouldn't need to write a conversion-webhook to safely work across them (mostly bigger schema changes) - We should probably test that the operator continues to function without new fields being present in API responses though (or that it at least fails gracefully-ish) because I don't think we've actively done that yet.

I'm not sure of many places where a written policy or validator for k8s api schema versioning exist tho 😢