Bump markdown from 3.5 to 3.5.1

Bumps [markdown](https://github.com/Python-Markdown/markdown) from 3.5 to 3.5.1.
- [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@3.5...3.5.1)

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

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

requirements.txt

@@ -82,7 +82,7 @@ drf-extensions==0.7.1
 drf-writable-nested==0.7.0
 drf-spectacular==0.26.5
 dynamic-rest==2.1.2
-Markdown==3.5
+Markdown==3.5.1
 
 pinax-notifications==6.0.0
 pinax-ratings==4.0.0