feat(container): update image mongodb to v15.6.20

Author: clarknova99-bot[bot]

kubernetes/apps/database/mongodb/app/helmrelease.yaml

@@ -10,7 +10,7 @@ spec:
   chart:
     spec:
       chart: mongodb
-      version: 15.1.1
+      version: 15.6.20
       sourceRef:
         kind: HelmRepository
         name: bitnami