code: func (s *Submodule) UpdateContext(ctx context.Context, o *SubmoduleUpdateOptions) error {
  	return s.update(ctx, o, plumbing.ZeroHash)
  }
docs: // UpdateContext the registered submodule to match what the superproject
  // expects, the submodule should be initialized first calling the Init method or
  // setting in the options SubmoduleUpdateOptions.Init equals true.
  //
  // The provided Context must be non-nil. If the context expires before the
  // operation is complete, an error is returned. The context only affects to the
  // transport operations.