Struct modeling incoming email
@type address() :: {String.t(), String.t()}
@type t() :: %Webhoox.Webhook.Email{ event: String.t(), from: address() | nil, html: String.t() | nil, message_id: String.t(), raw_params: map(), sender: String.t() | nil, subject: String.t() | nil, text: String.t() | nil, timestamp: DateTime.t() | nil, to: [address()] | nil }