[Opus] Update to v1.2.1

media/cast/test/utility/audio_utility.cc

Index: media/cast/test/utility/audio_utility.cc
diff --git a/media/cast/test/utility/audio_utility.cc b/media/cast/test/utility/audio_utility.cc
index 844b2905fc6f279f7df05a239f2b80abc8fab083..436400a6fb91ae20d227912a1e0b38c5b3fb44b2 100644
--- a/media/cast/test/utility/audio_utility.cc
+++ b/media/cast/test/utility/audio_utility.cc
@@ -44,7 +44,7 @@ std::unique_ptr<AudioBus> TestAudioBusFactory::NextAudioBus(
 int CountZeroCrossings(const float* samples, int length) {
   // The sample values must pass beyond |kAmplitudeThreshold| on the opposite
   // side of zero before a crossing will be counted.
-  const float kAmplitudeThreshold = 0.03f;  // 3% of max amplitude.
+  const float kAmplitudeThreshold = 0.02f;  // 2% of max amplitude.
 
   int count = 0;
   int i = 0;