The OCP 4.15 release notes failed to include a deprecation notice for the prometheus-adapter component, whose functionality is being replaced by metrics server.

Note that this change will require the OCP docs change management process: https://docs.google.com/document/d/1fLMpK4bqthtFlCwA36yeo2cI-pExFpX76VMnSi_In6Q/edit?pli=1#bookmark=id.khm4rxl210qm

We need to add the deprecation information to the following places in the 4.15 RNs:

• in the Monitoring deprecated and removed features table in https://docs.openshift.com/container-platform/4.15/release_notes/ocp-4-15-release-notes.html#ocp-4-15-deprecated-removed-features

• In the list at https://docs.openshift.com/container-platform/4.15/release_notes/ocp-4-15-release-notes.html#ocp-4-15-deprecated-features

See https://github.com/openshift/enhancements/blob/master/enhancements/monitoring/replace-prometheus-adapter-with-metrics-server.md#graduation-criteria for more info about this deprecation.