Update redis Docker tag to v21.2.6

Author: renovate[bot]

infrastructure/database/redis/operator/kustomization.yaml

@@ -9,7 +9,7 @@ resources:
 helmCharts:
   - name: redis
     repo: oci://registry-1.docker.io/bitnamicharts
-    version: 21.2.5
+    version: 21.2.6
     releaseName: redis
     namespace: redis
     includeCRDs: true