Add 🐍 version `3.13` to build-and-test matrix

[michplunkett]

Description of Changes

Adding Python version 3.13 to the testing matrix so that we can get ahead of the curve when it comes to dealing with deprecations, etc.

Tests and Linting

• [x] This branch is up-to-date with the develop branch.
• [x] pytest passes on my local development environment.
• [x] pre-commit passes on my local development environment.

[michplunkett]

Gonna put this bb on 🧊 until there's a more established image of v3.13.

[michplunkett]

This isn't ready yet. I'll ping you when it is, @b-meson!