Log Message:
py-test-rerunfailures: updated 8.0

8.0:
Backwards incompatible changes
- Drop support for pytest version 3.10, 4.0, 4.1, 4.2 and 4.3
- Drop support for Python 3.4.

Features
- Add support for pytest version 4.4, 4.5, 4.6, 5.0, 5.1 and 5.2.

Bug fixes
- Explicitly depend on setuptools to ensure installation when working in
  environments without it.