chore: 🧑‍💻 use justfile as checklist in template

[lwjohnst86]

Description

This PR makes very small updates to the justfile and simplifies the checklist in the PR template to tell submitter to run just run-all as a check.

This PR needs a quick review.

[signekb]

Looks fine to me. Do we need to include build-website in run-all though?
It just takes a while to build the website and could be a bit annoying to have to do that every time you e.g., create a new function?

[lwjohnst86]

@signekb you wouldn't run just run-all every time you commit, only right before pushing up to make a PR. Just so we can minimize the chance of build errors on the GitHub action side.

[signekb]

I also meant for creating a small PR like adding a new function - so not every commit, but every PR. But lets give it a try 👍