I would say that the change in pattern of elimination is probably not related to the diet change. I would continue with house training efforts as it sounds like you were making progress especially since you have only had him one week. There is a shift in water intake that occurs when you go to dry food only. Canned or moist foods are about 70% water so a puppy on that type of diet does not need to drink much. When you go to dry food he has to increase voluntary water intake so there could be a temporary shift in urine output but his total water intake in a day will balance out over a few days. I would keep doing what you are doing and see what happens in the next couple days, if the frequent urination continues let me know and I will help you decide what to do next.
Spiteful urination to protest the change would be very unusual in a puppy this young and new.