pyhepmc: a Pythonic interface to HepMC3

pyhepmc is a Pythonic frontend for the HepMC3 library and part of Scikit-HEP. It allows one to read/write HepMC3 records in various formats and to convert any other particle record to HepMC3. pyhepmc was originally proposed to become the official Python interface for HepMC3. HepMC3 eventually got an alternative Python interface which is an automatic translation of the C++ interface, while pyhepmc offers a hand-written interface with a Pythonic feel. Another advantage of pyhepmc is that it is listed on PyPI and can be easily installed with pip, thanks to Scikit-HEP releasing binary wheels for common platforms.