Code review comment for ~cjwatson/launchpad:ci-build-upload-make-spr

I am with Andrey in that we should not use a dictionary.

While attrs is a great library, I am -0.5 on introducing it.

Introducing a new dependency
- which it is only used for two classes
- only for a short interim period
- with a new "syntax"
- which is even dated, ie it is not reflected in the main documentation of the package - you need to dive into its history: https://www.attrs.org/en/stable/names.html#a-short-history-lesson

I am strongly in favor of using plain classes - with that usual boilerplate - and convert them to dataclasses once we are on a suitable Python version.

If you go forward using it, please leave a comment to remove it asap.