Seattle startup Picnic raised an additional $3 million from existing investors as it gears up for a commercial rollout of its pizza-making robot. Vulcan Capital, Flying Fish Partners, Creative Ventures, Arnold Venture Group, and others put more money behind Picnic, known for its automated food preparation device that can churn out up to 300 12-inch customized pizzas per hour. It follows a $5 million seed round in November. The fresh cash will be used for product development, response to customer interest, new hires, and marketing.