Bump markdown from 3.8.2 to 3.9 (#13118)

Bumps [markdown](https://github.com/Python-Markdown/markdown) from 3.8.2 to 3.9.
- [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@3.8.2...3.9.0)

---
updated-dependencies:
- dependency-name: markdown
  dependency-version: '3.9'
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

Author: dependabot[bot]

requirements.txt

@@ -28,7 +28,7 @@ humanize==4.13.0
 jira==3.8.0
 PyGithub==2.7.0
 lxml==6.0.1
-Markdown==3.8.2
+Markdown==3.9
 openpyxl==3.1.5
 Pillow==11.3.0  # required by django-imagekit
 psycopg[c]==3.2.9