Update README.md

demos/README.md

-# Demos for PaddleSpeech
+# Speech Application based on PaddleSpeech
+
+The directory containes many speech applications in multi scenarios.
+
+* audio tagging  - tag audio label in vedio  
+* metaverse  - 2D AR with TTS  
+* speech recogintion - vidio understanding  
+* speech translation - end to end speech translation  
+* story talker - book reader based on OCR and TTS  
+* style_fs2 - multi style control for FastSpeech2 model