pkg_resources is deprecated and will be removed

[stanislavlevin]

https://setuptools.pypa.io/en/stable/history.html#v80-9-0

Set a deadline for the removal of pkg_resources later this year (December). (#3085)

[cdent]

See #105 which starts but does not finish the work.

As I stated there, if someone is willing to provide the full patch, I'll release a version that contains it, but ideally people will stop using paste.