Making changes to a user (administratively or as the user).

See UsersUpdate.update @spec for details on args. Explains for said args:

• user_changes map is variable, in that it's keys may vary based on the input args sent into GraphQL updatePerson() mutation
• caller_authz is the level of authorization for the caller, which changes what updates are allowed.
• target_user is optional, if nil the user should be created, if exists then it's an update for that user

Example (create):

  ==> Rivet.Ident.UsersUpdate.update(%{
      action: :upsert,
      user: %{name: "The Doctor"},
      email: %{email: "who@tardis.com"}
    }, :admin)
  {:ok, %User{}, %{"password": "R^EkW)aBY9G9", "passwordExp": 1649947803}}

Rivet.Ident.UsersUpdate.update(%{ action: :upsert, user: %{name: "The Doctor"}, email: %{email: "who@tardis.com"} }, :admin)

Example — update a user's name as the user

  ==> Rivet.Ident.UsersUpdate.update(%{
    action: :upsert,
    user: %{name: "Who"},
  }, :user, %User{...})
  {:ok, %User{}, %{}}

Example — remove a phone

  ==> Rivet.Ident.UsersUpdate.update(%{
    action: :remove,
    phone: %{id: "2342343-...-33"},
  }, :user, %User{...})
  {:ok, %User{}, %{}}