0.3.0 Use splat syntax to return Node Group underlying resources

what

• Use splat syntax to return Node Group underlying resources

why

• Use splat syntax in outputs, it prevents errors when looking for resources which could not exist anymore, particularly during a destroy action

references

• https://discuss.hashicorp.com/t/empty-tuple-error-on-modules-that-are-disabled/4544
• hashicorp/terraform#22846

related

• Closes #7