Merge pull request #756 from Justin-ZL/dev

add:openai text to speech

metagpt/provider/openai_api.py

@@ -235,3 +235,7 @@ class OpenAILLM(BaseLLM):
     async def amoderation(self, content: Union[str, list[str]]):
         """Moderate content."""
         return await self.aclient.moderations.create(input=content)
+
+    async def atext_to_speech(self, **kwargs):
+        """text to speech"""
+        return await self.aclient.audio.speech.create(**kwargs)