🌱 Bump markdown from 3.4.4 to 3.5.2 (#589)

Bumps [markdown](https://github.com/Python-Markdown/markdown) from 3.4.4 to 3.5.2.
- [Release notes](https://github.com/Python-Markdown/markdown/releases)
- [Changelog](https://github.com/Python-Markdown/markdown/blob/master/docs/changelog.md)
- [Commits](Python-Markdown/markdown@3.4.4...3.5.2)

---
updated-dependencies:
- dependency-name: markdown
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

docs/requirements.txt

@@ -9,7 +9,7 @@ ghp-import==2.1.0
 idna==3.4
 Jinja2==3.1.3
 lxml==4.9.3
-Markdown==3.4.4
+Markdown==3.5.2
 markdown2==2.4.10
 MarkupSafe==2.1.3
 mergedeep==1.3.4