Add the func list_cluster_monitoring_user_credentials in the vendored sdk for the version v2020_01_01#1188

mmyyrroonn merged 3 commits intoAzure:masterAzure/azure-cli-extensions:masterfrom

bingosummer:aks-cluster-monitoring-userbingosummer/azure-cli-extensions:aks-cluster-monitoring-userCopy head branch name to clipboard