Bump jinja2 from 3.0.3 to 3.1.3 in /docs

Bumps [jinja2](https://github.com/pallets/jinja) from 3.0.3 to 3.1.3.
- [Release notes](https://github.com/pallets/jinja/releases)
- [Changelog](https://github.com/pallets/jinja/blob/main/CHANGES.rst)
- [Commits](pallets/jinja@3.0.3...3.1.3)

---
updated-dependencies:
- dependency-name: jinja2
  dependency-type: direct:production
...

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

docs/requirements.txt

@@ -8,4 +8,4 @@ pomegranate >= 1.0.0
 sphinx-rtd-theme
 pandoc
 nbsphinx
-jinja2==3.0.3
+jinja2==3.1.3