title: What is the replacement for tf.contrib.layers.layer_norm() in TensorFlow 2.0?
body: <p>It seems that TF 2.0 does not have <code>tf.contrib</code>. Then, what is the replacement for <code>tf.contrib.layers.layer_norm()</code>? I didn't find it in <code>tensorflow_addons</code> too.</p>