Inheritance: extends App\Http\Requests\InvoiceRequest
 /**
  * @SWG\Delete(
  *   path="/invoices",
  *   tags={"invoice"},
  *   summary="Delete an invoice",
  *   @SWG\Parameter(
  *     in="body",
  *     name="body",
  *     @SWG\Schema(ref="#/definitions/Invoice")
  *   ),
  *   @SWG\Response(
  *     response=200,
  *     description="Delete invoice",
  *      @SWG\Schema(type="object", @SWG\Items(ref="#/definitions/Invoice"))
  *   ),
  *   @SWG\Response(
  *     response="default",
  *     description="an ""unexpected"" error"
  *   )
  * )
  */
 public function destroy(UpdateInvoiceAPIRequest $request)
 {
     $invoice = $request->entity();
     $this->invoiceRepo->delete($invoice);
     return $this->itemResponse($invoice);
 }