boto should be removed from optional dependencies

[David Runge]

Hi! 👋

I maintain this project as a package for Arch Linux. We're currently cleaning up and dropping packages not compatible with Python 3.12, en route to updating to this newer Python interpreter.

I noticed that the boto upstream is deprecated and as such it should be removed from this project (and or its use be replaced with something else, e.g. boto3).
We will remove boto from the official repositories and in turn I will remove boto from the optional dependencies of the package on Arch Linux as well.

Thanks for your work 🙇