Update pluggy to 0.6.0

[pyup-bot]

There's a new version of pluggy available.
You are currently using 0.5.2. I have updated it to 0.6.0

These links might come in handy: PyPI | Changelog | Repo

Changelog

0.6.0

---

• Add CI testing for the features, release, and master
  branches of pytest (PR 79_).
• Document public API for _Result objects passed to wrappers
  (PR 85_).
• Document and test hook LIFO ordering (PR 85_).
• Turn warnings into errors in test suite (PR 89_).
• Deprecate _Result.result (PR 88_).
• Convert _Multicall to a simple function distinguishing it from
  the legacy version (PR 90_).
• Resolve E741 errors (PR 96_).
• Test and bug fix for unmarked hook collection (PRs 97_ and
  102_).
• Drop support for EOL Python 2.6 and 3.3 (PR 103_).
• Fix inspect based arg introspection on py3.6 (PR 94_).

.. _79: pytest-dev/pluggy#79
.. _85: pytest-dev/pluggy#85
.. _88: pytest-dev/pluggy#88
.. _89: pytest-dev/pluggy#89
.. _90: pytest-dev/pluggy#90
.. _94: pytest-dev/pluggy#94
.. _96: pytest-dev/pluggy#96
.. _97: pytest-dev/pluggy#97
.. _102: pytest-dev/pluggy#102
.. _103: pytest-dev/pluggy#103

Got merge conflicts? Close this PR and delete the branch. I'll create a new PR for you.

Happy merging! 🤖