fix encoding issue (#97)

sift/client.py

@@ -934,7 +934,7 @@ def _validate_send_request(self, properties):
             session_id, 'session_id', error_cls=ValueError)
 
     def verification_resend(self, properties, timeout=None,  version=None):
-        """A user can ask for a new OTP (one-time password) if they haven’t received the previous one,
+        """A user can ask for a new OTP (one-time password) if they haven't received the previous one,
         or in case the previous OTP expired.
         This call is blocking. Check out https://sift.com/developers/docs/python/verification-api/resend
         for more information on our send response structure.