support mod_google_tts_streaming

lib/tasks/tts-task.js

@@ -140,6 +140,13 @@ class TtsTask extends Task {
           ...(reduceLatency && {RIMELABS_TTS_STREAMING_REDUCE_LATENCY: reduceLatency})
         };
         break;
+      case 'google':
+        obj = {
+          GOOGLE_TTS_LANGUAGE_CODE: language,
+          GOOGLE_TTS_VOICE_NAME: voice,
+          GOOGLE_APPLICATION_CREDENTIALS: JSON.stringify(credentials)
+        };
+        break;
       default:
         if (vendor.startsWith('custom:')) {
           const use_tls = custom_tts_streaming_url.startsWith('wss://');