[ReleasePR orbital] Published/azure/azure rest api specs pr/dev orbital microsoft.orbital 2021 04 04 preview (#2065)

Create to sync Azure/azure-rest-api-specs#16877
[ReCreate this PR](https://github.com/azure-resource-manager-schemas/compare/main...AzureSDKAutomation:sdkAuto/orbital?expand=1)

Author: msftbot[bot]

schemas/2021-04-04-preview/Microsoft.Orbital.json

@@ -332,6 +332,10 @@
           ],
           "description": "Auto track configuration."
         },
+        "eventHubUri": {
+          "type": "string",
+          "description": "The URI of the Event Hub used for telemetry"
+        },
         "links": {
           "oneOf": [
             {