3.2.0rc0

Changed:

• Removed support for Python 2
• This version only supporting Python 3.10, 3.11, 3.12
• All docstrings style updated to numpydoc

Deprecated:

• Deprecated the diffpy.structure.applications module. Use
  diffpy.structure.apps instead

Removed:

• Removed all six compatibility code

Fixed:

• Repo structure modified to the new diffpy standard