Update docker.io/library/redis Docker tag to v8.8

Author: renovate[bot]

kubernetes/apps/security/authentik/app/redis.yaml

@@ -16,7 +16,7 @@ spec:
     spec:
       containers:
         - name: redis
-          image: docker.io/library/redis:8.2-alpine
+          image: docker.io/library/redis:8.8-alpine
           ports:
             - containerPort: 6379
               name: redis