Include changes to pyproject.toml creation in next changelog #908

Another thing to do - we shouldn't create pyproject.toml anymore unless it's truly necessary. With the none backend, we aren't adding deps in the pyproject.toml file (or anywhere), just displaying a message, so it shouldn't be necessary to create this file.

Originally posted by @nathanjmcdougall in #826 (comment)

This is a major change but I don't want to miss documenting it.