Update prometheus to v2.15.1

Signed-off-by: Amir Zarrinkafsh <[email protected]>

Update pushgateway to v1.0.1

Signed-off-by: Amir Zarrinkafsh <[email protected]>

Update alertmanager to v0.20.0

Signed-off-by: Amir Zarrinkafsh <[email protected]>

Update cadvisor to v0.34.0

Container location updated to gcr.io/google-containers due to google/cadvisor#2301

Update grafana to v6.5.1

Signed-off-by: Amir Zarrinkafsh <[email protected]>

Update grafana to v6.5.0

Update grafana to v6.5.0-beta1 and utilise provisioning system

Update prometheus to v2.14.0

Update prometheus to v2.13.1

Update prometheus to v2.13.0