Merge branch 'pw/3.0-default-initial-branch-to-main'

Declare that "git init" that is not otherwise configured uses 'main' as the initial branch, not 'master', starting Git 3.0. * pw/3.0-default-initial-branch-to-main: t0613: stop setting default initial branch t9902: switch default branch name to main t4013: switch default branch name to main breaking-changes: switch default branch to main