Description of the problem, including code/CLI snippet

As a user of the python-gitlab library, I would like to be able to call the /projects/:id/members/all/:user_id endpoint, described as in the official documentation:
https://docs.gitlab.com/ee/api/members.html#get-a-member-of-a-group-or-project-including-inherited-members

This goes hand in hand with Groups as well.

Expected Behavior

Being able to call the endpoint.

Actual Behavior

Not able to call the endpoint.

Specifications

• python-gitlab version: 2.3.1
• API version you are using (v3/v4): latest, doesn't matter
• Gitlab server version (or gitlab.com): latest, doesn't matter