chore(deps): bump markdown from 3.6 to 3.7

Bumps [markdown](https://github.com/Python-Markdown/markdown) from 3.6 to 3.7.
- [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@3.6...3.7)

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

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

docs/requirements-docs.txt

@@ -1,4 +1,4 @@
-markdown==3.6
+markdown==3.7
 mkdocs==1.6.0
 mkdocs-material==9.5.31
 mdx_truly_sane_lists==1.3