Bump recommonmark from 0.5.0 to 0.6.0

Bumps [recommonmark](https://github.com/rtfd/recommonmark) from 0.5.0 to 0.6.0.
- [Release notes](https://github.com/rtfd/recommonmark/releases)
- [Changelog](https://github.com/readthedocs/recommonmark/blob/master/CHANGELOG.md)
- [Commits](readthedocs/recommonmark@0.5.0...0.6.0)

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

docs/requirements.txt

@@ -4,7 +4,7 @@
 sphinx==2.1.2
 sphinx_autodoc_typehints==1.7.0
 sphinx-click==2.2.0
-recommonmark==0.5.0
+recommonmark==0.6.0
 m2r==0.2.1
 tomlkit==0.5.5