Bump flask from 2.3.2 to 3.1.3 in /test/acceptance

Bumps [flask](https://github.com/pallets/flask) from 2.3.2 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@2.3.2...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>

Author: dependabot[bot]

test/acceptance/requirements.txt

@@ -1,6 +1,6 @@
 lettuce==0.2.20
 fabric==1.10.0
-flask==2.3.2         # blindly changing from 0.12.3 due to a github vulnerability warning, not yet tested...
+flask==3.1.3         # blindly changing from 0.12.3 due to a github vulnerability warning, not yet tested...
 requests==2.31.0      # blindly change from 2.20.0 (test/acceptance is no longer in use)
 colorama==0.2.5
 paramiko==3.4.0     # blindly changing from 2.0.9 due to a github vulnerability warning, not yet tested...