3.6.1

Added:

• update isort, flake8 and black to set line limit to 79

Fixed:

• Support scikit-package Level 5 standard (https://scikit-package.github.io/scikit-package/).
• Update github CI to scikit-package standard
• Let DiffractionObject.get_array_index to use the xtype from its inputs.

Removed:

• Extra line break in each news after 3.6.0 in CHANGELOG.rst so that this rst can be rendered correctly when deployed