scikit-hep/boost-histogram: Version 1.0.0

Dropped support for Python 2 and 3.5; removed large numbers of workarounds. Fully statically typed. API compatible with the final 0.x release for most uses, except for subclassing; subclassing histogram components now uses Python 3 class keyword syntax to set families.

• Dropped Python 2.7 and 3.5 support #512
• Removed deprecated .options from axes. Use .traits instead. #503
• Full static typing available, UHI 0.1.2+ supported. #516, #517, #519, #520, #521, #523

• Use keyword class family setting when subclassing histogram components instead of custom decorator. #513
• Structure of internal repr creation changed and made slightly more public. #518

• Consistently show metadata= in repr if present; refactored internal repr handling #518
• Minor typing related fixes for rare bugs (especially in numpy.py, #521)