The United States Postal Service (USPS) is issuing an urgent warning to Americans to keep their dogs secured during mail deliveries after more than 5,200 postal workers were attacked by canines last year. The warning comes as the USPS kicks off its annual Dog Bite Awareness campaign, a month-long June initiative aimed at reducing attacks on mail carriers and promoting  responsible pet ownership . “Every single day, our postal employees serve their communities across dynamic, fast-changing