why :membership_type and :role are not added to the changeset

change.ex

  def update_changeset(membership, attrs) do
    dbg(membership)
    dbg(attrs)
    # attrs #=> %{is_paid: false, membership_type: "personal", role: "admin"}

    to_atom_attrs =
      Enum.map(attrs, fn {k, v} ->
        if is_atom(v) do
          {k, v}
        else
          {k, String.to_existing_atom(v)}
        end
      end)
      |> Enum.into(%{})

    dbg(to_atom_attrs)
    # to_atom_attrs #=> %{is_paid: false, membership_type: :personal, role: :admin}

    membership
    |> cast(to_atom_attrs, [:role, :is_paid, :membership_type])
    |> validate_required([:role])
    |> validate_inclusion(:role, @role_options)
    |> prepare_changes(fn changeset ->
      current_role = membership.role
      new_role = get_change(changeset, :role)

      dbg(new_role)
      # new_role #=> nil

      # changeset #=> #Ecto.Changeset<
      #   action: :update,
      #   changes: %{is_paid: false},
      #   errors: [],
      #   data: #Markably.Orgs.Membership<>,
      #   valid?: true
      # >

      if current_role == @admin_role && new_role != current_role do
        validate_at_least_one_admin(changeset)
      else
        changeset
      end
    end)

defmodule Markably.Orgs.Membership do
  use Markably.Schema
  # use Ecto.Schema
  # import Ecto.Changeset
  import Ecto.Query
  import MarkablyWeb.Gettext

  alias Markably.Orgs.Org
  alias Markably.Accounts.User

  @role_options ~w(admin member)a
  @default_role :member
  @admin_role :admin

  schema "orgs_memberships" do
    field :role, Ecto.Enum, values: @role_options
    # , default: false
    field :is_paid, :boolean
    field :membership_type, Ecto.Enum, values: [:personal, :enterprise], default: :personal

    # field :billing_subscription, Ecto.Enum, values: [:personal_free, :personal_monthly, :personal_quarterly, :personal_biannually, :personal_yearly, :enterprise], default: :personal_free

    belongs_to :user, User
    belongs_to :org, Org

    timestamps()
  end