fix(git): add vendor in .gitignore

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

@@ -1,16 +0,0 @@
-//go:build appengine || js || nacl
-// +build appengine js nacl
-
-package isatty
-
-// IsTerminal returns true if the file descriptor is terminal which
-// is always false on js and appengine classic which is a sandboxed PaaS.
-func IsTerminal(fd uintptr) bool {
-	return false
-}
-
-// 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
-}