opts.go
func ProjectID(projectID string) Option {
	return func(sh *StackdriverHook) error {
		sh.projectID = projectID
		return nil
	}
}
func ProjectID(projectID string) Option {
	return func(sh *StackdriverHook) error {
		sh.projectID = projectID
		return nil
	}
}
// ProjectID is an option that sets the project ID which is needed for the log
// name.