Add `checkout-default` alias info
Add `checkout-default` alias info

Not all repos use `master` as the default branch any more, so add an
alias to `.gitconfig` to find the current repo's default branch and
switch to it.

Signed-off-by: Joe Block <13bb081c6ac072ef78a3e348068e2204400d7335@unixorn.net>

unixorn/git-extra-commands,unixorn/git-extra-commands,unixorn/git-extra-commands,unixorn/git-extra-commands