Updated MarkItDown API Server

Hey there! Markitdown-api wraps Microsoft's official MarkItDown library in a lightweight FastAPI REST server packed in a Docker image. You POST a file (PDF, Word, Excel, etc.) and it returns a clean Markdown string that can be used in RAG and LLM pipelines. This release is a security-focused dependency refresh. The recent BadHost issue in Starlette (which FastAPI is bui