Description of the problem, including code/CLI snippet

The Gitlab API contains a new feature to createprotected tags. It would be awesome if this capability was added to this library.

Expected Behavior

Able to create protected tags for roles AND users (see#653).

Actual Behavior

No functionality exists.

Specifications

• python-gitlab version: 1.6
• API version you are using (v3/v4): v4
• Gitlab server version (or gitlab.com): 11.3