build(deps): bump flask in /tests/opentelemetry-docker-tests/tests (#4249)

Bumps [flask](https://github.com/pallets/flask) from 3.0.2 to 3.1.3.
- [Release notes](https://github.com/pallets/flask/releases)
- [Changelog](https://github.com/pallets/flask/blob/main/CHANGES.rst)
- [Commits](pallets/flask@3.0.2...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>
Co-authored-by: dependabot[bot] <49699333+dependabot[bot]@users.noreply.github.com>
Co-authored-by: Riccardo Magliocchetti <riccardo.magliocchetti@gmail.com>

Author: dependabot[bot]

tests/opentelemetry-docker-tests/tests/test-requirements.txt

@@ -24,7 +24,7 @@ dockerpty==0.4.1
 docopt==0.6.2
 exceptiongroup==1.2.0
 flaky==3.7.0
-flask==3.0.2
+flask==3.1.3
 greenlet==3.0.3
 grpcio==1.63.2
 idna==3.7