Keras-tuner

Bug fixes
* Changed the chief server waiting time before shutting down to 60 minutes
by default.

New features

Bug fixes
* When running in parallel, the chief may exit before some client ask for
another trial, which informs the client to exit. Now, it is fixed.

New features
* Updated the dependency from `keras-core` to `keras` version 3 and above. Also
support `keras` version 2 for backward compatibility.

Bug fixes
* When running in parallel, the client oracle used to wait forever when the
chief oracle is not responding. Now, it is fixed.
* When running in parallel, the client would call the chief after calling
`oracle.end_trial()`, when the chief have already ended. Now, it is fixed.
* When running in parallel, the chief used to start to block in
`tuner.__init__()`. However, it makes more sense to block when calling
`tuner.search()`. Now, it is fixed.
* Could not do `from keras_tuner.engine.hypermodel import HyperModel`. It is now
fixed.
* Could not do `from keras_tuner.engine.hyperparameters import HyperParameters`.
It is now fixed.
* Could not do `from keras_tuner.engine.metrics_tracking import
infer_metric_direction`. It is now fixed.
* Could not do `from keras_tuner.engine.oracle import Objective`. It is now
fixed.
* Could not do `from keras_tuner.engine.oracle import Oracle`. It is now fixed.

Bug fixes
* Could not do `from keras_tuner.engine.hyperparameters import serialize`. It is
now fixed.
* Could not do `from keras_tuner.engine.hyperparameters import deserialize`. It
is now fixed.
* Could not do `from keras_tuner.engine.tuner import maybe_distribute`. It is
now fixed.

Bug fixes
* Could not do `from keras_tuner.engine.tuner import Tuner`. It is now fixed.
* When TensorFlow version is low, it would error out with keras models have no
attributed called `get_build_config`. It is now fixed.

Bug fixes
* Could not do `from keras_tuner.engine import trial`. It is now fixed.