Bump pytest from 5.4.2 to 6.2.4

Bumps [pytest](https://github.com/pytest-dev/pytest) from 5.4.2 to 6.2.4.
- [Release notes](https://github.com/pytest-dev/pytest/releases)
- [Changelog](https://github.com/pytest-dev/pytest/blob/main/CHANGELOG.rst)
- [Commits](pytest-dev/pytest@5.4.2...6.2.4)

---
updated-dependencies:
- dependency-name: pytest
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

requirements/testing.txt

@@ -5,7 +5,7 @@ flake8==3.9.2
 flake8-isort==2.8.0
 pydocstyle==6.1.1
 pylint==2.5.2
-pytest==5.4.2
+pytest==6.2.4
 pytest-cov==2.12.1
 pytest-timeout==1.3.4
 setuptools==57.4.0