dependabot: bump flask-session from 0.6.0 to 0.8.0

Bumps [flask-session](https://github.com/pallets-eco/flask-session) from 0.6.0 to 0.8.0.
- [Release notes](https://github.com/pallets-eco/flask-session/releases)
- [Changelog](https://github.com/pallets-eco/flask-session/blob/development/CHANGES.rst)
- [Commits](https://github.com/pallets-eco/flask-session/commits/0.8.0)

---
updated-dependencies:
- dependency-name: flask-session
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

requirements.txt

@@ -1,5 +1,5 @@
 cs50==9.3.4
-Flask-Session==0.6.0
+Flask-Session==0.8.0
 Flask==3.0.3
 gunicorn==22.0.0
 numpy>=1.22.2 # not directly required, pinned to avoid a vulnerability