Bump flask from 1.0.2 to 3.1.3 in /examples/server/wsgi

Bumps [flask](https://github.com/pallets/flask) from 1.0.2 to 3.1.3.
- [Release notes](https://github.com/pallets/flask/releases)
- [Changelog](https://github.com/pallets/flask/blob/main/CHANGES.rst)
- [Commits](https://github.com/pallets/flask/compare/1.0.2...3.1.3)

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

Signed-off-by: dependabot[bot] <[email protected]>

examples/server/wsgi/requirements.txt

@@ -2,7 +2,7 @@ Click==7.0
 enum-compat==0.0.2
 enum34==1.1.6
 eventlet==0.40.3
-Flask==1.0.2
+Flask==3.1.3
 greenlet==0.4.12
 itsdangerous==1.1.0
 Jinja2==3.1.6