chore(speech to text example): Adjust speech to text example 'requires'

maxnussbaum · maxnussbaum · commit 318512629f81 · 2018-07-11T15:20:23.000-04:00
diff --git a/examples/speech_to_text_v1.rb b/examples/speech_to_text_v1.rb
@@ -1,7 +1,6 @@
 # frozen_string_literal: true
 
 require("ibm_watson/speech_to_text_v1")
-require("ibm_watson/recognize_callback")
 
 # If using IAM
 speech_to_text = IBMWatson::SpeechToTextV1.new(
