docs(quantization.md): remove ppq commit (#1095)

docs/en/02-how-to-run/quantize_model.md

@@ -30,7 +30,6 @@ Currently mmdeploy support ncnn with PTQ.
 ```bash
 git clone https://github.com/openppl-public/ppq.git
 cd ppq
-git checkout edbecf4 # import some feature
 pip install -r requirements.txt
 python3 setup.py install
 ```

docs/zh_cn/02-how-to-run/quantize_model.md

@@ -29,7 +29,6 @@ mmdeploy 基于静态图（onnx）生成推理框架所需的量化表，再用
 ```bash
 git clone https://github.com/openppl-public/ppq.git
 cd ppq
-git checkout edbecf4 # 需要一些特性和修复
 pip install -r requirements.txt
 python3 setup.py install
 ```