chore(deps): Bump flask in /examples/knative/python/kn-py-vro

Bumps [flask](https://github.com/pallets/flask) from 2.1.2 to 2.3.2.
- [Release notes](https://github.com/pallets/flask/releases)
- [Changelog](https://github.com/pallets/flask/blob/main/CHANGES.rst)
- [Commits](pallets/flask@2.1.2...2.3.2)

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

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

examples/knative/python/kn-py-vro/requirements.txt

@@ -2,7 +2,7 @@ cloudevents==1.2.0
   deprecation==2.1.0
     packaging==21.3
       pyparsing==3.0.9
-Flask==2.1.2
+Flask==2.3.2
   click==8.1.3
   importlib-metadata==4.11.4
     zipp==3.8.0