Log Message:
py-test-cov: updated to 2.8.1

2.8.1:
* Fixed regression when only certain reports (html or xml) are used then \ 
``--cov-fail-under`` always fails.

2.8.0:
* Fixed ``RecursionError`` that can occur when using
  `cleanup_on_signal \ 
<https://pytest-cov.readthedocs.io/en/latest/subprocess-support.html#if-you-got-custom-signal-handling>`__ \ 
or
  `cleanup_on_sigterm \ 
<https://pytest-cov.readthedocs.io/en/latest/subprocess-support.html#if-you-got-custom-signal-handling>`__.
  The 2.7.x releases of pytest-cov should be considered broken regarding \ 
aforementioned cleanup API.
* Added compatibility with future xdist release that deprecates some internals
  (match pytest-xdist master/worker terminology).
* Fixed breakage that occurs when multiple reporting options are used.
* Changed internals to use a stub instead of ``os.devnull``.
* Added support for Coverage 5.0.
* Added support for float values in ``--cov-fail-under``.
* Various documentation fixes.
* Various testing improvements.
* Added the ``--cov-context`` CLI options that enables coverage contexts. Only \ 
works with coverage 5.0+.