Bump pytest from 6.1.0 to 6.1.1 in /docs (#662)

Bumps [pytest](https://github.com/pytest-dev/pytest) from 6.1.0 to 6.1.1.
- [Release notes](https://github.com/pytest-dev/pytest/releases)
- [Changelog](https://github.com/pytest-dev/pytest/blob/master/CHANGELOG.rst)
- [Commits](pytest-dev/pytest@6.1.0...6.1.1)

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

Co-authored-by: dependabot-preview[bot] <27856297+dependabot-preview[bot]@users.noreply.github.com>

Author: dependabot-preview[bot]

docs/requirements.txt

@@ -14,5 +14,5 @@ pygments==2.7.1
 # Dependencies of our project:
 typing-extensions==3.7.4.3
 mypy==0.782
-pytest==6.1.0
+pytest==6.1.1
 hypothesis==5.37.0