v0.5.0

Enhancements:

1. New Function get_anthropic_completion/2: This function calls the AnthropicHTTPClient.complete method, providing an interface to get completions from the Anthropic API.
2. Updated Module Documentation: The moduledoc now includes information about the new function and its purpose, along with the existing OpenAI functions.
3. Examples and Options: Added an example for using get_anthropic_completion/2 and listed the relevant options for configuring the Anthropic API request.