post https://api.notion.com/v1/file_uploads
Use this API to initiate the process of uploading a file to your Notion workspace.
For a successful request, the response is a File Upload object with a status of "pending".
The maximum allowed length of filename string is 900 bytes, including any file extension included in the file name or inferred based on the content_type. However, we recommend using shorter names for performance and easier file management and lookup using the List file uploads API.