[windows] skip 'UNIX only'

# Test that chezmoi init runs run_before_ scripts before executing templates
env PATH=$PATH:$HOME/bin
exec chezmoi init --apply
cmp $HOME/.file golden/.file

-- golden/.file --
output
-- golden/binary.sh --
#!/bin/sh

echo output
-- home/user/.local/share/chezmoi/dot_file.tmpl --
{{ output "binary.sh" -}}
-- home/user/.local/share/chezmoi/run_before_install-binary.sh --
#!/bin/sh

cp $WORK/golden/binary.sh $HOME/bin
chmod a+x $HOME/bin/binary.sh
-- home/user/bin/.keep --
