Bump flask in /scripts/docker/examples/python/assets/hello_world

Bumps [flask](https://github.com/pallets/flask) from 2.3.3 to 3.1.3.
- [Release notes](https://github.com/pallets/flask/releases)
- [Changelog](https://github.com/pallets/flask/blob/main/CHANGES.rst)
- [Commits](pallets/flask@2.3.3...3.1.3)

---
updated-dependencies:
- dependency-name: flask
  dependency-version: 3.1.3
  dependency-type: direct:production
...

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

Author: dependabot[bot]

scripts/docker/examples/python/assets/hello_world/requirements.txt

@@ -1,7 +1,7 @@
 blinker==1.6.2
 click==8.1.7
 Flask-WTF==1.2.0
-Flask==2.3.3
+Flask==3.1.3
 itsdangerous==2.1.2
 Jinja2==3.1.5
 MarkupSafe==2.1.3