Add support for uploading buffer instead of filepath

[Signorlupo22]

This pull request introduces the ability to upload data using a buffer rather than a filepath. By allowing buffer uploads, the code becomes more flexible and can handle data streams directly, which can be particularly useful for in-memory data processing and scenarios where file system access is limited or undesirable. The changes include modifications to the upload function to accept buffer inputs, as well as updates to relevant tests to ensure proper functionality.

[abhinaba-ghosh]

Thanks for raising this PR. As this is a breaking change, would you mind updating the readme accordingly?

Thanks in advance!

[Signorlupo22]

Thank you for your feedback. I will update the README accordingly and make the necessary changes as soon as possible.

Thanks in advance for your patience!

Best regards,

[Signorlupo22]

I've updated the README to include the new buffer upload functionality and added support for PPTX files. If you need any further changes or have additional requests, please let me know.