message: [skip ci] update next release with hera integration
diff: We are pleased to announce the release 3.X.X of the GUDHI library.
  -As a major new feature, the GUDHI library now offers ...
  +As a major new feature, the GUDHI library now offers a Python interface to [Hera](https://bitbucket.org/grey_narn/hera/src/master/) to compute the Wasserstein distance.
  +[PyBind11](https://github.com/pybind/pybind11) is now required to build the Python module.
  We are now using GitHub to develop the GUDHI library, do not hesitate to [fork the GUDHI project on GitHub](https://github.com/GUDHI/gudhi-devel). From a user point of view, we recommend to download GUDHI user version (gudhi.3.X.X.tar.gz).
  -Below is a list of changes made since GUDHI 3.X-1.X-1:
  +Below is a list of changes made since GUDHI 3.1.1:
  -- [Module](link)
  - - ...
  +- [Wassertein distance](https://gudhi.inria.fr/python/latest/wasserstein_distance_user.html)
  + - An another implementation comes from Hera (BSD-3-Clause) which is based on [Geometry Helps to Compare Persistence Diagrams](http://doi.acm.org/10.1145/3064175) by Michael Kerber, Dmitriy Morozov, and Arnur Nigmetov.
  - [Module](link)
  - ...
  - Miscellaneous
  - - The [list of bugs that were solved since GUDHI-3.X-1.X-1](https://github.com/GUDHI/gudhi-devel/issues?q=label%3A3.1.1+is%3Aclosed) is available on GitHub.
  + - The [list of bugs that were solved since GUDHI-3.1.1](https://github.com/GUDHI/gudhi-devel/issues?q=label%3A3.2.0+is%3Aclosed) is available on GitHub.
  All modules are distributed under the terms of the MIT license.
  However, there are still GPL dependencies for many modules. We invite you to check our [license dedicated web page](https://gudhi.inria.fr/licensing/) for further details.
  