Log Message:
py-test-runner: updated to 5.1

5.1:
Surgically restore support for older setuptools versions.

5.0
Prefer pyproject.toml

Refresh package metadata.

This release now intentionally introduces the changes unintionally brought about \ 
in 4.5 and 4.3, where the adoption of declarative config adds a new requirement \ 
on setuptools 30.4 or later. On systems running older setuptools, installation \ 
of pytest-runner via easy_install (or setup_requires), will result in a \ 
DistributionNotFound exception.

All projects should pin to pytest-runner < 5 or upgrade the environment to \ 
setuptools >= 30.4 (prior to invoking setup.py).