Amazon racks up the celebrity deals on Prime Day

Will Smith is selling water. Kobe Bryant is pushing deodorant. Mark Wahlberg is peddling protein powder. YouTube star JoJo Siwa, known for wearing big, colorful hair bows, is hawking, well, big colorful hair bows.Amazon.com Inc. is tapping high-profile actors, athletes and social-media sensations to maintain buzz around its Prime Day summer sale, now in its fifth year and battling increasing competition from rivals.Discounted pressure cookers and gadgets just aren't enough to stand out when shop