Allow options `,inline,omitempty`

[morlay]

Marshal failed with https://github.com/kubernetes/api/blob/master/networking/v1/types.go#L418

May consider to support this case.

[dsnet]

Hi, I'm not sure I understand what ,inline,omitempty means.

• The "omitempty" option specifies that the struct field should be omitted if the field value would have been encoded as a JSON null, empty string, empty object, or empty array.

• The "inline" option specifies that the JSON representable content of this field type is to be promoted as if they were specified in the parent struct.

I don't understand what it means for both of these options to be used together.

I argue that Kubernetes should fix the generation of their types to stop an invalid combination of tag options.

[morlay]

@dsnet Sure, it make sence. I just want to confirm the tag options limit here will be landing in json/v2.