message: update description of use_calib in README
diff: @@ -188,7 +188,7 @@ python3 -m paddle_serving_server.serve --model uci_housing_model --thread 10 --p
  | `use_lite` (Only for Intel x86 CPU or ARM CPU) | - | - | Run PaddleLite inference |
  | `use_xpu` | - | - | Run PaddleLite inference with Baidu Kunlun XPU |
  | `precision` | str | FP32 | Precision Mode, support FP32, FP16, INT8 |
  -| `use_calib` | bool | False | Only for deployment with TensorRT |
  +| `use_calib` | bool | False | Use TRT int8 calibration |
  | `gpu_multi_stream` | bool | False | EnableGpuMultiStream to get larger QPS |
  #### Description of asynchronous model
  