code: public MonitorService deleteLabel(String monitorId, Label label)
      {
          HTTP.DELETE(String.format("/v1/monitors/%s/labels/%s", monitorId, label.getKey()));
          return this;
      }
docs: Deletes the given label from the monitor with the given id.
  @param monitorId The id of the monitor with the label
  @param label The label to delete
  @return This object