message: Message enrichment spec change for iot hub
diff: "fallbackRoute": {
  "description": "The properties of the route that is used as a fall-back route when none of the conditions specified in the 'routes' section are met. This is an optional parameter. When this property is not set, the messages which do not meet any of the conditions specified in the 'routes' section get routed to the built-in eventhub endpoint.",
  "$ref": "#/definitions/FallbackRouteProperties"
  + },
  + "enrichments": {
  + "description": "The list of user-provided enrichments that the IoT hub applies to messages to be delivered to built-in and custom endpoints. See: https://aka.ms/telemetryoneventgrid",
  + "type": "array",
  + "items": {
  + "$ref": "#/definitions/EnrichmentProperties"
  + }
  }
  }
  },
  "isEnabled"
  ]
  },
  + "EnrichmentProperties": {
  + "description": "The properties of an enrichment that your IoT hub applies to messages delivered to endpoints.",
  + "type": "object",
  + "properties": {
  + "key": {
  + "description": "The key or name for the enrichment property.",
  + "type": "string"
  + },
  + "value": {
  + "description": "The value for the enrichment property.",
  + "type": "string"
  + },
  + "endpointNames": {
  + "description": "The list of endpoints for which the enrichment is applied to the message.",
  + "minItems": 1,
  + "type": "array",
  + "items": {
  + "type": "string"
  + }
  + }
  + },
  + "required": [
  + "key",
  + "value",
  + "endpointNames"
  + ]
  + },
  "IotHubDescription": {
  "description": "The description of the IoT hub.",
  "type": "object",
  