2.2.0

Changelog

Version 2.2.0 (2021-03-24)

• --track-memory option now supports macOS by using psutil.
• Added --copy-env command line option that inherits all environment variables.
• The development branch master was renamed to main.
  See https://sfconservancy.org/news/2020/jun/23/gitbranchname/ for the
  rationale.