v1.19.8
copier: add GetOptions.IgnoreUnreadable
Set upperdir permissions based on source
ADD/COPY: create the destination directory first, chroot to it
copier.GetOptions: add NoDerefSymLinks
copier: return child process stderr if we can't JSON decode the response
copier: fix a renaming bug
copier: add an Eval function
copier.GetOptions: add NoDerefSymLinks