[cli-ref] Update python-magnumclient to 2.0.0
[cli-ref] Update python-magnumclient to 2.0.0

Closes-Bug: #1520193
Change-Id: I8b90fb513233fcd926a9c740567f3ef2ee0f603b

openstack/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals,openstack/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals,AlekhyaMallina-Vedams/openstack-manuals