Pyhepmc

What's Changed
* Support reading/writing compressed files by HDembinski in https://github.com/scikit-hep/pyhepmc/pull/44

**Full Changelog**: https://github.com/scikit-hep/pyhepmc/compare/v2.6.1...v2.7.0

What's Changed
* Fix license issues by HDembinski in https://github.com/scikit-hep/pyhepmc/pull/38
* Increase coverage by HDembinski in https://github.com/scikit-hep/pyhepmc/pull/41


**Full Changelog**: https://github.com/scikit-hep/pyhepmc/compare/v2.6.0...v2.6.1

What's Changed
* Particles can be assigned as attributes by HDembinski in https://github.com/scikit-hep/pyhepmc/pull/39
* Attributes after deserialisation are now represented by the UnparsedAttribute class, which allows conversion into concrete attribute types by HDembinski in https://github.com/scikit-hep/pyhepmc/pull/39

**Full Changelog**: https://github.com/scikit-hep/pyhepmc/compare/v2.5.1...v2.6.0

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