Change branch from "master" to "main"

[kersten1]

As a gentle reminder, the "Friendly Terminology" policy link which uses the "Inclusive Naming" community link includes the word "master" as a Tier 1: Replace Immediately word.

You can follow these steps to rename your branch: https://gist.github.com/danieldogeanu/739f88ea5312aaa23180e162e3ae89ab

[jrtc27]

Unlike just replacing terms in documents, renaming branches is disruptive to everyone who has cloned the repository, so I'm loathe to do this unless it's deemed actually important (and from what I read online at the time this was a hot topic of discussion, it was deemed dubious whether this use of the term was actually offensive, but got bundled up with the movement regardless). In my day job we've done this for many of our repositories, but we have a tool that automatically manages local clones so were able to switch branches locally too for the users.