author_id and committer_id is missing in REST v4 Commits API
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### Summary
Unable to get commit author and committer relevant information. Currently API returns only names and emails instead of detailed author and committer info or at least their IDs.
<!-- Summarize the bug encountered concisely. -->
### Steps to reproduce
Call commits API (https://docs.gitlab.com/ee/api/commits.html#list-repository-commits)
<!-- Describe how one can reproduce the issue - this is very important. Please use an ordered list. -->
### What is the current *bug* behavior?
API returns only author's and committer's name and email.
<!-- Describe what actually happens. -->
### What is the expected *correct* behavior?
API should return user ID as well to simplify linkage to appropriate users
<!-- Describe what you should see instead. -->
### Possible fixes
Include author_id and committer_id to API response.
<!-- If you can, link to the line of code that might be responsible for the problem. -->
issue