According to official docs the settings for setupMaster settings are just the ClusterSettings.
There is an ClusterSettings interface already but setupMaster function parameters refered to incomplete and unnecessary ClusterSetupMasterSettings. I deleted the ClusterSetupMasterSettings interface and refer to the existing ClusterSettings which are correct.

https://nodejs.org/docs/latest-v8.x/api/cluster.html#cluster_cluster_setupmaster_settings

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