Add new audio file formats of the tts api

[GunniBusch]

See https://platform.openai.com/docs/guides/text-to-speech/supported-output-formats

[rattrayalex]

This change is has already been incorporated:

openai-openapi/openapi.yaml

Lines 6935 to 6940 in 6b64280

	Supported formats are `mp3`, `opus`, `aac`, `flac`, `pcm`, and `wav`.
	The `pcm` audio format, similar to `wav` but without a header, utilizes a 24kHz sample rate, mono channel, and 16-bit depth in signed little-endian format.
	default: "mp3"
	type: string
	enum: ["mp3", "opus", "aac", "flac", "pcm", "wav"]