Update pytest to 3.1.3

[pyup-bot]

There's a new version of pytest available.
You are currently using 3.1.2. I have updated it to 3.1.3

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

Changelog

3.1.3

=========================

Bug Fixes

• Fix decode error in Python 2 for doctests in docstrings. (2434 <https://github.com/pytest-dev/pytest/issues/2434>_)

• Exceptions raised during teardown by finalizers are now suppressed until all
  finalizers are called, with the initial exception reraised. (2440 <https://github.com/pytest-dev/pytest/issues/2440>_)

• Fix incorrect "collected items" report when specifying tests on the command-
  line. (2464 <https://github.com/pytest-dev/pytest/issues/2464>_)

• deprecated_call in context-manager form now captures deprecation warnings
  even if the same warning has already been raised. Also, deprecated_call
  will always produce the same error message (previously it would produce
  different messages in context-manager vs. function-call mode). (2469 <https://github.com/pytest-dev/pytest/issues/2469>_)

• Fix issue where paths collected by pytest could have triple leading /
  characters. (2475 <https://github.com/pytest-dev/pytest/issues/2475>_)

• Fix internal error when trying to detect the start of a recursive traceback.
  (2486 <https://github.com/pytest-dev/pytest/issues/2486>_)

Improved Documentation

• Explicitly state for which hooks the calls stop after the first non-None
  result. (2493 <https://github.com/pytest-dev/pytest/issues/2493>_)

Trivial/Internal Changes

• Create invoke tasks for updating the vendored packages. (2474 <https://github.com/pytest-dev/pytest/issues/2474>_)

• Update copyright dates in LICENSE, README.rst and in the documentation.
  (2499 <https://github.com/pytest-dev/pytest/issues/2499>_)

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

Happy merging! 🤖