message: update api scenario schema
diff: "type": "object",
  "properties": {
  "scope": {
  - "type": "string",
  - "enum": [
  - "ResourceGroup",
  - "Subscription",
  - "Tenant",
  - "None"
  - ],
  - "default": "ResourceGroup"
  + "$ref": "#/definitions/Scope"
  },
  "authentication": {
  "$ref": "#/definitions/Authentication"
  }
  ]
  },
  + "Scope": {
  + "type": "string",
  + "oneOf": [
  + {
  + "enum": ["ResourceGroup", "Subscription", "Tenant", "None"],
  + "default": "ResourceGroup"
  + },
  + {
  + "format": "uri-reference",
  + "pattern": "^.+\\.(yaml|yml)$"
  + }
  + ]
  + },
  "JsonPointer": {
  "type": "string",
  "description": "JSON Pointer described by RFC 6901, e.g. /foo/bar",
  