Fix typo in AM config field static_configs (#3415)
Fix typo in AM config field static_configs (#3415)

* typo in prometheus.yml field causes prometheus to throw an error

Fixes #3414
keegancsmith/prometheus,alileza/prometheus,alileza/prometheus,brancz/prometheus,Stackdriver/stackdriver-prometheus,brancz/prometheus,AlekSi/prometheus,AlekSi/prometheus,Stackdriver/stackdriver-prometheus,AlekSi/prometheus,Conorbro/prometheus,kangwoo/prometheus,keegancsmith/prometheus,prometheus/prometheus,Conorbro/prometheus,GoogleCloudPlatform/prometheus,Gouthamve/prometheus,AlekSi/prometheus,alileza/prometheus,kangwoo/prometheus,Conorbro/prometheus,Gouthamve/prometheus,keegancsmith/prometheus,Stackdriver/stackdriver-prometheus,GoogleCloudPlatform/prometheus,amorken/prometheus,prometheus/prometheus,amorken/prometheus,prometheus/prometheus,GoogleCloudPlatform/prometheus,alileza/prometheus,Gouthamve/prometheus,brancz/prometheus,kangwoo/prometheus,prometheus/prometheus,keegancsmith/prometheus,prometheus/prometheus,Stackdriver/stackdriver-prometheus,keegancsmith/prometheus,brancz/prometheus,amorken/prometheus,GoogleCloudPlatform/prometheus,alileza/prometheus,Conorbro/prometheus,GoogleCloudPlatform/prometheus,amorken/prometheus,Gouthamve/prometheus,kangwoo/prometheus