Sidecar image with private registry & authentication in air-gapped environment

Follow-up on https://github.com/cloudnative-pg/plugin-barman-cloud/issues/391

Hello,

I understand I can modify the location of the sidecar image with an env variable in the operator deployment and it works fine with our lab environment, where we use the harbor registry and no auth.
That said, we are required to use other registries from dev to prod environments and I don't understand how I can define imagePullSecrets for the sidecar container since it's not a regular PodSpec resource.

Any advice or suggestion ?

For the record, we transitioned all other images ( controllers + PG) to our internal registry with authentication, no issue.

Thanks