Tensorflow Federated 0.11.0

Major Features and Improvements

• Python 2 support is now deprecated and will be removed in a future release.
• federated_map now works with both tff.SERVER and tff.CLIENT
  placements.
• federated_zip received significant performance improvements and now works
  recursively.
• Added retry logic to gRPC calls in the execution stack.

Breaking Changes

• collections.OrderedDict is now required in many places rather than
  standard Python dictionaries.

Bug Fixes

• Fixed computation of the number of examples when Keras is using multiple
  inputs.
• Fixed an assumption that tff.framework.Tuple is returned from
  IterativeProcess.next.
• Fixed argument packing in polymorphic invocations on the new executor API.
• Fixed support for dir() in ValueImpl.
• Fixed a number of issues in the Colab / Jupyter notebook tutorials.