TensorFlow Federated 0.47.0

Release 0.47.0

Major Features and Improvements

• Added a LayoutMap message in the computation proto for TensorFlow
  DTensor based execution.

Breaking Changes

• Removed the compiler_fn parameter from the high level
  *_mergeable_execution_context functions.

Bug Fixes

• Aligned the context types allowed by the
  tff.program.NativeFederatedContext and the
  tff.program.PrefetchingDataSource.
• Updated build_functional_model_delta_update to use ReduceDataset ops to
  rely on MLIR Bridge for XLA compilation and TPU usage.