Clarify branch naming/not creating release-x branches for patch/RC.
Clarify branch naming/not creating release-x branches for patch/RC.

Signed-off-by: Callum Styan <106b387c595dcc1a235f6eff749ea0675b25b42d@gmail.com>

keegancsmith/prometheus,prometheus/prometheus,GoogleCloudPlatform/prometheus,GoogleCloudPlatform/prometheus,kangwoo/prometheus,prometheus/prometheus,alileza/prometheus,alileza/prometheus,prometheus/prometheus,alileza/prometheus,keegancsmith/prometheus,prometheus/prometheus,GoogleCloudPlatform/prometheus,prometheus/prometheus,kangwoo/prometheus,Gouthamve/prometheus,keegancsmith/prometheus,alileza/prometheus,kangwoo/prometheus,Gouthamve/prometheus,GoogleCloudPlatform/prometheus,keegancsmith/prometheus,GoogleCloudPlatform/prometheus,Gouthamve/prometheus,Gouthamve/prometheus,alileza/prometheus,kangwoo/prometheus,keegancsmith/prometheus