Langchain::Assistant works with AWS Bedrock-hosted Anthropic models

[andreibondarev]

Langchain::Assistant can now be used with Langchain::LLM::AwsBedrock models, initially only with Anthropic ones.

llm = Langchain::LLM::AwsBedrock.new(default_options: {chat_completion_model_name: "anthropic.claude-3-5-sonnet-20240620-v1:0"})

assistant = Langchain::Assistant.new(
  llm: llm,
  instructions: "You're a helpful AI assistant",
  tools: [Langchain::Tool::NewsRetriever.new(api_key: ENV["NEWS_API_KEY"])]
)

# Add a user message and run the assistant
assistant.add_message_and_run!(content: "What's the latest news about AI?")