Pyhepmc

What's Changed
* Fixed segfault in GenCrossSection by making Python API safer than C++ API by HDembinski in https://github.com/scikit-hep/pyhepmc/pull/36
* Update docs with example notebook by HDembinski in https://github.com/scikit-hep/pyhepmc/pull/37


**Full Changelog**: https://github.com/scikit-hep/pyhepmc/compare/v2.5.0...v2.5.1

What's Changed
* pythonic generated_mass by HDembinski in https://github.com/scikit-hep/pyhepmc/pull/30
* Docs by HDembinski in https://github.com/scikit-hep/pyhepmc/pull/31
* improved version sourcing by HDembinski in https://github.com/scikit-hep/pyhepmc/pull/32
* stricter type checking, type improvements, public io module by HDembinski in https://github.com/scikit-hep/pyhepmc/pull/33
* Attribute support by HDembinski in https://github.com/scikit-hep/pyhepmc/pull/34

**Full Changelog**: https://github.com/scikit-hep/pyhepmc/compare/v2.4.2...v2.5.0

What's Changed
* include tool in name, fix ratio for sibyll, attributes for toolset by HDembinski in https://github.com/scikit-hep/pyhepmc/pull/29


**Full Changelog**: https://github.com/scikit-hep/pyhepmc/compare/v2.4.1...v2.4.2

What's Changed
* prettier visualization by HDembinski in https://github.com/scikit-hep/pyhepmc/pull/28


**Full Changelog**: https://github.com/scikit-hep/pyhepmc/compare/v2.4.0...v2.4.1

What's Changed
* handle invalid particles and events without history by HDembinski in https://github.com/scikit-hep/pyhepmc/pull/27


**Full Changelog**: https://github.com/scikit-hep/pyhepmc/compare/v2.3.0...v2.4.0

What's Changed
* more flexible open function, support for convertible events by HDembinski in https://github.com/scikit-hep/pyhepmc/pull/26


**Full Changelog**: https://github.com/scikit-hep/pyhepmc/compare/v2.2.0...v2.3.0