Delete master branch
It's really annoying to accidentally check out the
master branch instead of
main, build and find out you wasted 10-20 minutes building the wrong thing -- or to accidentally type
git rebase master shudders.
I think enough time has passed that we can safely delete the
master branch for good.
This would cause
git checkout master to error out instead of checking out an ancient branch that's divergent because of the README change to it.