Add text-to-speech

examples/text_to_speech.rs

@@ -0,0 +1,21 @@
+use openai_api_rs::v1::api::Client;
+use openai_api_rs::v1::audio::{self, AudioSpeechRequest, TTS_1};
+use std::env;
+
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let client = Client::new(env::var("OPENAI_API_KEY").unwrap().to_string());
+
+    let req = AudioSpeechRequest::new(
+        TTS_1.to_string(),
+        String::from("Money is not problem, Problem is no money"),
+        audio::VOICE_ALLOY.to_string(),
+        String::from("problem.mp3"),
+    );
+
+    let result = client.audio_speech(req)?;
+    println!("{:?}", result);
+
+    Ok(())
+}
+
+// OPENAI_API_KEY=xxxx cargo run --package openai-api-rs --example text_to_speech