Bump pytest from 5.4.1 to 5.4.2 in /test/functional

Bumps [pytest](https://github.com/pytest-dev/pytest) from 5.4.1 to 5.4.2.
- [Release notes](https://github.com/pytest-dev/pytest/releases)
- [Changelog](https://github.com/pytest-dev/pytest/blob/master/CHANGELOG.rst)
- [Commits](pytest-dev/pytest@5.4.1...5.4.2)

Signed-off-by: dependabot-preview[bot] <[email protected]>