Add release notes for start of Newton support

The Newton release is here, in preparation for the Tempest 13.0.0
release we need to add details to the release notes about the supported
releases. Once this merges we should be ready to land the 13.0.0
release.

Change-Id: I3774fcb7753155cfe38d0de36d6e162ff25591b6
1 file changed