function buildLinearRegressionModel(inputShape) {
  const model = tf.sequential();
  model.add(tf.layers.flatten({inputShape}));
  model.add(tf.layers.dense({units: 1}));
  return model;
}
Build a linear-regression model for the temperature-prediction problem.

@param {tf.Shape} inputShape Input shape (without the batch dimenson).
@returns {tf.LayersModel} A TensorFlow.js tf.LayersModel instance.