scikit-hep/particle: 0.7.0

Enhancements to Particle class: Dummy/unknown particle width and lifetime errors stored as None. More particle name and PDGID literals for b-baryons. Fix for the D(s2)*(2573) LaTeX name. InvalidParticle made available at top-level import. Changes in API: Particle.from_dec...() renamed to Particle.from_evtgen_name(...). MC particle identification code converters: Introduced directional maps PDG2EvtGenNameMap and EvtGen2PDGNameMap between PDG and EvtGen names. Conversions master file data/conversions.csv added. Content of converters CSV files are now ordered. Documentation: README updated with new package functionality. Support for Python 3.4 removed and support for Python 3.8 added