Bump jinja2 from 3.1.2 to 3.1.3 in /examples/flask/app (awslabs#333)

Bumps [jinja2](https://github.com/pallets/jinja) from 3.1.2 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@3.1.2...3.1.3)

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

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

Author: dependabot[bot]

examples/flask/app/requirements.txt

@@ -4,7 +4,7 @@ Flask==2.3.2
 gunicorn==20.1.0
 importlib-metadata==6.6.0
 itsdangerous==2.1.2
-Jinja2==3.1.2
+Jinja2==3.1.3
 MarkupSafe==2.1.2
 Werkzeug==3.0.1
 zipp==3.15.0