members.all returns dicts instead of REST objects #699

Description of the problem, including code/CLI snippet

project.members.all() is documented as returning a RESTObjectList, but it actually returns a list of dicts. Same for groups.

Expected Behavior

all() should return a list of the same type as list().

Actual Behavior

>>> type(gitlab.Gitlab.from_config().projects.list()[0].members.list()[0])
<class 'gitlab.v4.objects.ProjectMember'>
>>> type(gitlab.Gitlab.from_config().projects.list()[0].members.all()[0])
<class 'dict'>

Specifications

• python-gitlab version: 1.7.0
• API version you are using (v3/v4): v4
• Gitlab server version (or gitlab.com): Shouldn't matter.