add:openai text to speech

tests/metagpt/provider/test_openai.py

@@ -42,6 +42,18 @@ async def test_aask_code_message():
     assert len(rsp["code"]) > 0
 
 
+@pytest.mark.asyncio
+async def test_text_to_speech():
+    llm = LLM()
+    resp = await llm.atext_to_speech(
+        model="tts-1",
+        voice="alloy",
+        input="人生说起来长，但知道一个岁月回头看，许多事件仅是仓促的。一段一段拼凑一起，合成了人生。苦难当头时，当下不免觉得是折磨；回头看，也不够是一段短短的人生旅程。",
+    )
+    assert 200 == resp.response.status_code
+
+
+
 class TestOpenAI:
     def test_make_client_kwargs_without_proxy(self):
         instance = OpenAILLM(mock_llm_config)