gcloud-metadata feature request

[johngillott]

Hello 👋

I'm writing a library that depends on gcloud-auth & gcloud-metadata (thank you btw).

Are you open to adding getter functions to the metadata API to expose Zone ID & Instance ID information?

Happy to contribute if you find the above agreeable.

[yoshidan]

Thank you very much.
If you can add it, I will merge it.

[yoshidan]

Since gcloud-metada is based on google-cloud-go, this may be helpful.

https://github.com/googleapis/google-cloud-go/blob/main/compute/metadata/metadata.go