TensorFlow Lattice v2.1.0

Changes:

• Updating keras imports to use tf_keras (for TF >= 2.16 tf.keras defaults to Keras-3).
• Deprecating Estimators and Visualization library (removed in TF >= 2.16).
• All docs and tutorials converted to use Keras premade models instead of Estimators.

PyPI Release:

• Generic package for py3 and TF 2.x.