Bump markdown from 3.3.4 to 3.8.1 in /libraries/lvgl-8.2.0/docs

Bumps [markdown](https://github.com/Python-Markdown/markdown) from 3.3.4 to 3.8.1.
- [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@3.3.4...3.8.1)

---
updated-dependencies:
- dependency-name: markdown
  dependency-version: 3.8.1
  dependency-type: direct:production
...

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

Author: dependabot[bot]

libraries/lvgl-8.2.0/docs/requirements.txt

@@ -9,7 +9,7 @@ idna==2.10
 imagesize==1.2.0
 importlib-metadata==4.0.1
 Jinja2==2.11.3
-Markdown==3.3.4
+Markdown==3.8.1
 MarkupSafe==1.1.1
 packaging==20.9
 Pygments==2.9.0