Hypothesis API: user.update

Tracking issue: https://github.com/bibliotechie/antithesis/issues/29

What it does

A PATCH request to /users/{username} modifies the information for that user. Note that this is not for a user modifying their own profile, as it's intended to be run by an authority with the requisite authorization, not regular users.

Do we need it?

There is no obvious reason we would ever need to implement this.

What it looks like

Not yet recorded; for now, just look at the official API docs.