Remove pypy (2) environment from tox.ini
Remove pypy (2) environment from tox.ini

pypy refers to Pypy 2 which implements Python 2 which pytest does not
support. Keep only pypy3.

Akasurde/pytest,pytest-dev/pytest,nicoddemus/pytest,RonnyPfannschmidt/pytest,nicoddemus/pytest,The-Compiler/pytest,The-Compiler/pytest,markshao/pytest