v0.9.0

• kubecfg validate now ignores object kinds that are not found in the server discovery data by default.
  This matches the behaviour of kubectl, and allows CRDs to "just work" (ie: be silently ignored) in more cases. See --ignore-unknown flag to force other behaviour.
• Phase 1 for migrating the gc-tag from an annotation to a label.
  In this release, kubecfg --gc-tag=... writes the gc-tag to both the old annotation and new label, but continues to read from the annotation. A future version will move to the label exclusively - see #205 for overall progress.
• Improve error message when kubecfg encounters an unexpected jsonnet result structure.
• null values at object level in jsonnet results are now silently ignored.
  This is sometimes seen in helm template output, and is also useful to conditionally "whiteout" objects. Note null values within objects are still preserved at this stage.
• client-go upgraded to kubernetes-1.10.3
  • As part of this upgrade, kubecfg now uses the server's OpenAPI schema and not Swagger.