I’m having the same problem. It happened 4 days ago too. I changed all the passwords for everything – WP users, FTP users, Hosting account, etc, double checked the database for breeches and then did a clean WP install. It was just hacked again using the same code this morning.
Very “relieved” to hear I’m not the only one having this problem, and that it’s an issue at GoDaddy and not something stupid I did.