Update example code to use latest ReazonSpeech API

Signed-off-by: Fujimoto Seiji <fujimoto@ceptord.net>

README.md

@@ -41,10 +41,11 @@ We recommend to use this model through our
 library.
 
 ```
-from reazonspeech.nemo.asr import load_model, transcribe
+from reazonspeech.nemo.asr import load_model, transcribe, audio_from_path
 
+audio = audio_from_path("speech.wav")
 model = load_model()
-ret = transcribe("speech.wav", model)
+ret = transcribe(model, audio)
 print(ret.text)
 ```