orSelector`, `spec.probeSelector`
and `spec.scrapeConfigSelector` are null, the Prometheus configuration is unmanaged.
The Prometheus operator will ensure that the Prometheus configuration's
Secret exists, but it is the responsibility of the user to provide the raw
gzipped Prometheus configuration under the `prometheus.yaml.gz` key.
This behavior is *deprecated* and will be removed in the next major version
of the custom resource definition. It is recommended to use
`spec.additionalScrapeConfigs` instead.²