Update Part 2 - Neural Networks in PyTorch (Exercises).ipynb

updated ```dataiter.next()``` to ```next(dataiter)``` as the former code will cause an attribute error

Author: AliKhaled11

intro-to-pytorch/Part 2 - Neural Networks in PyTorch (Exercises).ipynb

@@ -105,7 +105,7 @@
    "outputs": [],
    "source": [
     "dataiter = iter(trainloader)\n",
-    "images, labels = dataiter.next()\n",
+    "images, labels = next(dataiter)\n",
     "print(type(images))\n",
     "print(images.shape)\n",
     "print(labels.shape)"