docs need updating to reflect some api changes to the Client.update_all() call

[vegu]

https://github.com/peeringdb/peeringdb-py/blob/master/docs/api.md refers to update_all() which was lost during the refactoring in version 2.0.0.

It is now located at Client.updater.update_all - this feels like an oversight and we should probably still have it abstracted at Client.update_all - at the very least documentation needs updating.

Also double check we're not missing any other changes.

[jackcarrozzo]

+1

[grizz]

+1

[arnoldnipper]

+1