Update confluent-kafka requirement from <2.8.0,>=2.4.0 to >=2.4.0,<2.9.0

Updates the requirements on [confluent-kafka](https://github.com/confluentinc/confluent-kafka-python) to permit the latest version.
- [Release notes](https://github.com/confluentinc/confluent-kafka-python/releases)
- [Changelog](https://github.com/confluentinc/confluent-kafka-python/blob/master/CHANGELOG.md)
- [Commits](confluentinc/confluent-kafka-python@v2.4.0...v2.8.0)

---
updated-dependencies:
- dependency-name: confluent-kafka
  dependency-type: direct:production
...

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

pyproject.toml

@@ -79,7 +79,7 @@ prometheus = ["django-prometheus"]
 kafka = [
   # Pinned because project warns "things might (and will) break with every update"
   "cloudevents==1.11.0",
-  "confluent-kafka>=2.4.0,<2.8.0",
+  "confluent-kafka>=2.4.0,<2.9.0",
 ]
 
 [project.urls]