v4.8.1

Changed

• Added file valid_tags.txt to not break builds.
• TFDS no longer relies on TensorFlow DTypes. We chose NumPy DTypes to keep the
  typing expressiveness, while dropping the heavy dependency on TensorFlow. We
  migrated all our internal datasets. Please, migrate accordingly:
  • tf.bool: np.bool_
  • tf.string: np.str_
  • tf.int64, tf.int32, etc: np.int64, np.int32, etc
  • tf.float64, tf.float32, etc: np.float64, np.float32, etc