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] <[email protected]>

test_reqs.txt

@@ -15,7 +15,7 @@ mccabe==0.7.0
 python-dateutil==2.9.0.post0
 text-unidecode==1.3
 
-Markdown==3.6
+Markdown==3.7
 django-markdownify==0.9.5
 bleach==6.1.0
 webencodings==0.5.1