The induced voltage is proportional to the time derivative of the net magnetic flux density. This is called faradays law of magnetic induction. Because you have a north and a south pole right next to each other (assuming they are magnets of equal strength) the total net magnetic flux will be zero. This is because the north end of one magnet adds a positive flux while the south end of the other magnet contributes negative flux.
As a result, the induced EMF will be zero. (I'm almost done with my PhD in electromagnetics engineering, so you can take this answer to the bank :) )
