Description of the problem, including code/CLI snippet

The recently added project all function, projects = gl.projects.all(), doesn't seem to work.

Expected Behavior

It should traditionally return all projects.

Actual Behavior

AttributeError: 'ProjectManager' object has no attribute 'all'

Specifications

• python-gitlab version: 1.4.0
• API version you are using (v3/v4): v4
• Gitlab server version (or gitlab.com): gitlab.com