message: Update pooling.py
  Updated the value of strides argument in example snippet
diff: @@ -366,7 +366,7 @@ class MaxPooling2D(Pooling2D):
  ... [9., 10., 11., 12.]])
  >>> x = tf.reshape(x, [1, 3, 4, 1])
  >>> max_pool_2d = tf.keras.layers.MaxPooling2D(pool_size=(2, 2),
  - ... strides=(1, 1), padding='valid')
  + ... strides=(2, 2), padding='valid')
  >>> max_pool_2d(x)
  <tf.Tensor: shape=(1, 2, 3, 1), dtype=float32, numpy=
  array([[[[ 6.],
  