Rename "master" branch to "main"

[derks]

The term master is a tier-1 (replace immediately) word determined by the Inclusive Naming Initiative. As Github has made main the default branch, we want to rename master to main as the default development branch.

Refs:

• https://inclusivenaming.org/word-lists/tier-1/

[derks]

note to developers, you may meed to run the following per Github notes on renaming the default branch from master to main:

git branch -m master main
git fetch origin
git branch -u origin/main main
git remote set-head origin -a