v0.8.0

Enhancements:

1. New Function groq_completion/2: This function calls the GroqHTTPClient.complete method, providing an interface to get completions from the Groq API.
2. Updated Module Documentation: The moduledoc now includes information about the new function and its purpose.
3. Examples and Options: Add detailed options for configuring the Groq API requests have been added, giving users the flexibility to tailor their API calls according to specific requirements such as :model, :temperature, :top_p, top_k, :max_tokens, :stream, :stop and :timeout.