update vendor

vendor/github.com/mattn/go-isatty/isatty_bsd.go

@@ -1,18 +0,0 @@
-// +build darwin freebsd openbsd netbsd dragonfly
-// +build !appengine
-
-package isatty
-
-import "golang.org/x/sys/unix"
-
-// IsTerminal return true if the file descriptor is terminal.
-func IsTerminal(fd uintptr) bool {
-	_, err := unix.IoctlGetTermios(int(fd), unix.TIOCGETA)
-	return err == nil
-}
-
-// IsCygwinTerminal return true if the file descriptor is a cygwin or msys2
-// terminal. This is also always false on this environment.
-func IsCygwinTerminal(fd uintptr) bool {
-	return false
-}