change the default TTS model to TacotronDDC

TTS/bin/synthesize.py

@@ -68,7 +68,7 @@ def main():
     parser.add_argument(
         "--model_name",
         type=str,
-        default="tts_models/en/ljspeech/speedy-speech-wn",
+        default="tts_models/en/ljspeech/tacotron2-DDC",
         help="Name of one of the pre-trained tts models in format <language>/<dataset>/<model_name>",
     )
     parser.add_argument(