update README and document

docs/requirements.txt

 sphinx==2.1.0
 mistune
 sphinx_rtd_theme
-paddlepaddle>=1.6
+paddlepaddle>=1.8
 zmq

python/paddle_fl/mpc/examples/uci_demo/README.md

@@ -122,18 +122,18 @@ print("prediction:")
 process_data.load_decrypt_data("/tmp/uci_prediction", (BATCH_SIZE,))
 ```
 
-#### Convergence of paddle_fl.mpc vs paddle
+### 3. Convergence of paddle_fl.mpc vs paddle
 
-Below, is the result of our experiment to test the convergence of paddle_fl.mpc
+Below, is the result of our experiment to test the convergence of paddle_fl.mpc on single machine.
 
-#### A. Convergence of paddle_fl.mpc vs paddle
 
-##### 1. Training Parameters
+#### (1). Training Parameters
+
 - Dataset: Boston house price dataset
 - Number of Epoch: 20
 - Batch Size: 10
 
-##### 2. Experiment Results
+#### (2). Experiment Results
 
 | Epoch/Step | paddle_fl.mpc | Paddle |
 | ---------- | ------------- | ------ |

python/paddle_fl/mpc/examples/uci_demo/README_CN.md

@@ -124,15 +124,15 @@ print("prediction:")
 process_data.load_decrypt_data("/tmp/uci_prediction", (BATCH_SIZE,))
 ```
 
-#### A. 精度测试
+### 三. 单机精度测试
 
-##### 1. 训练参数
+#### 1. 训练参数
 
 - 数据集：波士顿房价预测。
 - 训练轮数： 20
 - Batch Size：10
 
-##### 2. 实验结果
+#### 2. 实验结果
 
 | Epoch/Step | paddle_fl.mpc | Paddle |
 | ---------- | ------------- | ------ |