separate out the drawPupils() function

Move the code for both pupils from draw()
to a new function named drawPupils().

Replace the original pupils code in draw()
with a call to the new function:
drawPupils()

The face should still appear as before.

function drawPupils() {
  // pupils
  // Left
  fill(0);
  ellipse(width/2 - 80, height/2 - 60, 40, 50);

  // Right
  fill(0);
  ellipse(width/2 + 80, height/2 - 60, 40, 50);
} //drawPupils