I dont belive there is a true hard counter to Yorick. However, several champs can do decently and possibly have a bit of advantage over him.
Cass is strong since she can poison at extreme range, push pretty well, and spam her serpent tooth if she does hit you. Yoricks sustain cannot keep up with that. She can keep Yorick at a distance for the most part, zone out him meleeing the creeps and her Ult, poison zone and spam can ensure that even if Yorick closes to melee, he will take massive damage.
Heimer is not really a counter. Good vs most, but Yorick has the advantage over heimer, even if its slight. Heimers long CDs ensure that if Yorick can W,E and approach in melee that he can beat down Heimer fairly hard. So it is a contest of skill.
Kayle was problematic against my Yorick, esp before gunblade nerf. Her big nuke/slow, with enhanced autoattacks hurt really bad and her heal/speedboost would help keep her from eating ghoul damage and keep me from closing to melee where I could use my Q and Ult to good effect.
Even a bad Talon was surprisingly difficult. His dagger throw slows, pushes creeps, and has better range than W,E. Plus he can flash on top of you with silence and his Ult is better than Yoricks Ult for 1v1.
Basically you need a champ that can PUSH pretty well...plus has decent RANGE and is not as vulnerable to melee...i.e. a stun, escape, or heavy melee damage ability.