Anthropic LLM Integration for LlamaIndex

The `llama-index-llms-anthropic` package provides an integration for using Anthropic's Claude models within the LlamaIndex framework. Anthropic is an AI research company focused on developing advanced language models, notably the Claude series, prioritizing safety and alignment. This integration allows LlamaIndex applications to leverage Anthropic's models for various LLM operations. The current version is `0.11.2`, and it follows LlamaIndex's rapid release cadence with frequent updates.