Describe operator upgrade step-by-step in documentation

[oneumyvakin]

• Which image of the operator are you using? e.g. registry.opensource.zalan.do/acid/postgres-operator:v1.8.0
• Where do you run it - cloud or metal? Kubernetes or OpenShift? [Bare Metal K8s]
• Are you running Postgres Operator in production? [I'm going to use operator in production]
• Type of issue? [improvement]

Current description of operator upgrade is too high level https://github.com/zalando/postgres-operator/blob/master/docs/administrator.md#upgrading-the-operator

Could you please improve with example of step-by-step command lines how to upgrade operator from 1.8.0 to 1.8.2 using Helm and without Helm?

[FxKu]

I think without helm it's really just updating the image in the deployment. In case there are breaking changes, I will list them in the next release notes.

We are not using helm so I cannot really provide a guide there. I'm aware that we might not follow correct guidelines for handling releases, but I need someone from the helm user community to fix it.