wal-g backup retention not working since 1.13.0

[bo0ts]

• Which image of the operator are you using? ghcr.io/zalando/postgres-operator:v1.13.0
• Where do you run it - cloud or metal? Kubernetes or OpenShift? OpenShift 4.15
• Are you running Postgres Operator in production? yes
• Type of issue? Bug

Since upgrading to postgres-operator 1.13.0 old wal-g backups are not deleted anymore.

We use the following backup related configuration:

kind: ConfigMap
apiVersion: v1
metadata:
  name: postgres-pod-config
data:
  AWS_ACCESS_KEY_ID: ...
  AWS_SECRET_ACCESS_KEY: ...
  AWS_S3_FORCE_PATH_STYLE: "true"
  AWS_REGION: ...
  AWS_ENDPOINT: ...
  USE_WALG_BACKUP: "true"
  USE_WALG_RESTORE: "true"
  WALG_DISABLE_S3_SSE: "true"
  WAL_S3_BUCKET: ...

We suspect that this is related to the following issue in Spilo https://github.com/zalando/spilo/issues/1015