Update README.md

demos/speech_translation/README.md

@@ -19,7 +19,7 @@ Here are sample files for this demo that can be downloaded:
 wget https://paddlespeech.bj.bcebos.com/PaddleAudio/zh.wav https://paddlespeech.bj.bcebos.com/PaddleAudio/en.wav
 ```
 
-### 3. Usage
+### 3. Usage (not support for Windows now)
 - Command Line(Recommended)
   ```bash
   paddlespeech st --input ./en.wav