Switch to Runic formatting

[graeme-a-stewart]

JuliaFormatter is having a few issues and we also got stuck at v1, because of v1/2 incompatibility.

As discussed in JuliaHEP/DistributionsHEP.jl#48, a switch to Runic would now be preferred, with nice arguments summarised by @szabo137:

---

Indeed, I can 😸

• simplicity (no config, no sync with other projects)
• better CI/CD integration (there is a maintained gh-action; JuliaFormatter needs some custom code around it, see here)
• speed (installation and running are way faster for larger projects)
• active maintenance
• better editor integration
• better integration with git-hooks (e.g. via pre-commit)

and finally, a very cool badge

---

We will target the upcoming v2.0.0 release for this.

[graeme-a-stewart]

Just to note, when this is done the commit should be added to .git-blame-ignore-revs.