Pipeline IID not return on API request

Summary

When accessing the Pipeline API to get the latest pipelines, no pipeline iid is listed.

Steps to reproduce

Make a API Request to get the latest pipelines for any project like the following example:

What is the current bug behavior?

No "iid": parameter was return in the get request. Only the "id": is returned.

What is the expected correct behavior?

The documentation describes that the "iid" is also returned https://docs.gitlab.com/ee/api/pipelines.html

Relevant logs and/or screenshots

Proposal

The team noted that these two areas (1, 2) may need changed to expose that in the GET response.