fix support precache audio with tts stream (#855)

* fix support precache audio with tts stream

* update speech util

lib/tasks/say.js

@@ -149,7 +149,7 @@ class TaskSay extends TtsTask {
             credentials,
             options: this.options,
             disableTtsCache : this.disableTtsCache,
-            preCache
+            renderForCaching: preCache
           });
           if (!filePath.startsWith('say:')) {
             this.logger.debug(`Say: file ${filePath}, served from cache ${servedFromCache}`);