update vendor

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

@@ -1,21 +0,0 @@
-// +build solaris
-// +build !appengine
-
-package isatty
-
-import (
-	"golang.org/x/sys/unix"
-)
-
-// IsTerminal returns true if the given file descriptor is a terminal.
-// see: https://src.illumos.org/source/xref/illumos-gate/usr/src/lib/libc/port/gen/isatty.c
-func IsTerminal(fd uintptr) bool {
-	_, err := unix.IoctlGetTermio(int(fd), unix.TCGETA)
-	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
-}