Support multiple prompts in CompletionRequest

[Code-Hex]

Hi 👋 Thanks for developing a great library!

Openai create-prompt documentation says the prompt field is supported encoded as a string, array of strings, array of tokens, or array of token arrays. but this library seems to be supported only encoded as a string.

openai-js implemented type for that like this: https://github.com/threepointone/openai-js/blob/eaade749f2ead531d2ac9a2015184f7b6418a581/api.ts#L475

So I want to ask the question, How can I send a completion request with an array of string?

Thanks

[jamiesun]

Use one API call to answer multiple questions

I think multiple questions should be supported, and this should be a way to maintain the context of the conversation

[vvatanabe]

@sashabaranov
This feature was implemented in PR #220. The requirements for this Issue have been met. Can you close this Issue?

Example:

CompletionRequest{
	Prompt:    []string{"Lorem ipsum", "Lorem ipsum", "Lorem ipsum"}, //use string or []string 
	Model:     GPT3Curie,
	MaxTokens: 5,
}

[vvatanabe]

Fixed #220