Pymatgen

* Bug fix to remove possibility of duplicate edges in `StructureGraph` (mkhorton, 2095)

* Element now has `ionization_energies`, `ionization_energy` and
`electron_affinity` properties.
* Extensive documentation has been added on pymatgen compatibility and the
new namespace architecture! We have also released a
`template repo <https://github.com/materialsproject/pymatgen-addon-template>`\_
to help new developers write add-ons for pymatgen! Check out our
:doc:`contributing page</contributing>` for details.

* Another bug fix release! Now SETTINGS have been moved to pymatgen.core.

* Bug fix release for missing package data files in v2022.0.1

* `pymatgen`, `pymatgen.ext`, `pymatgen.io` and `pymatgen.analysis` are now
namespace packages. Note that this does not affect normal usage of pymatgen
from v2022.0.0. All imports remain the same. However, it does allow developers
to write "add-ons" to these subpackages. A full documentation with examples
and templates is in the works to guide developers on how to write these
packages.

* This is the new version of pymatgen going forward. Root-level imports have been removed. Please see
<https://pymatgen.org/compatibility.html> on how to update your code for compatibility with v2022.