chore(deps): update bitnamilegacy/kafka docker tag to v3.9

Author: github-actions[bot]

charts/posthog/values.yaml

@@ -1261,7 +1261,7 @@ kafkaInit:
   enabled: true
   image:
     repository: bitnamilegacy/kafka
-    tag: "3.7"
+    tag: "3.9"
     pullPolicy: IfNotPresent
   topics:
     - cdp_backfill_events