corrected synthesize documentation from GET to POST

Author: mnr

watson_developer_cloud/text_to_speech_v1.py

@@ -34,7 +34,7 @@ def __init__(self, url=default_url, username=None, password=None, use_vcap_servi
 
     def synthesize(self, text, voice=None, accept=None, customization_id=None):
         """
-        Returns the get HTTP response by doing a GET to /synthesize with text, voice, accept
+        Returns the get HTTP response by doing a POST to /synthesize with text, voice, accept
         """
         params = {'voice': voice, 'accept': accept, 'customization_id': customization_id}
         data = {'text': text}