title: Why Huggingface create_optimizer method not working?
body: <p>How to use Huggingface create_optimizer method ?
  My code is as follows:</p>
  <pre><code>import tensorflow as tf
  from transformers import RobertaConfig, TFRobertaForMaskedLM, create_optimizer
  config = RobertaConfig()  
  optimizer,lr = create_optimizer(1e-4,1000000,10000,0.1,1e-6,0.01)
  training_loss = tf.keras.losses.SparseCategoricalCrossentropy(from_logits=True)
  model = TFRobertaForMaskedLM(config)
  model.compile(optimizer=optimizer, loss=training_loss)
  input = tf.random.uniform(shape=[1,25], maxval=100, dtype=tf.int32)
  hist = model.fit(input, input, epochs=1, steps_per_epoch=1,verbose=0)
  </code></pre>
  <p>I am getting an error:</p>
  <blockquote>
  <p>TypeError: apply_gradients() got an unexpected keyword argument
  'experimental_aggregate_gradients'</p>
  </blockquote>
  <p>I tried with tensorflow 2.3.0 and 2.2.0, transformers 3.0.2.</p>