Bump mkdocs from 1.4.0 to 1.4.2 in /docs/user (#254)

Bumps [mkdocs](https://github.com/mkdocs/mkdocs) from 1.4.0 to 1.4.2.
- [Release notes](https://github.com/mkdocs/mkdocs/releases)
- [Commits](mkdocs/mkdocs@1.4.0...1.4.2)

---
updated-dependencies:
- dependency-name: mkdocs
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>

docs/user/requirements.txt

@@ -1,4 +1,4 @@
-mkdocs==1.4.0
+mkdocs==1.4.2
 mkdocs-material==8.5.6
 mkdocstrings[python]==0.20.0
 mkdocstrings-python==0.8.3