[ReleasePR powerbidedicated] Dev powerbidedicated microsoft.power b idedicated 2021 01 01 (#2168)

Create to sync Azure/azure-rest-api-specs#16840
[ReCreate this PR](https://github.com/azure-resource-manager-schemas/compare/main...AzureSDKAutomation:sdkAuto/powerbidedicated?expand=1)

Author: msftbot[bot]

schemas/2021-01-01/Microsoft.PowerBIDedicated.json

@@ -252,6 +252,17 @@
     "CapacitySku": {
       "type": "object",
       "properties": {
+        "capacity": {
+          "oneOf": [
+            {
+              "type": "integer"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "The capacity of the SKU."
+        },
         "name": {
           "type": "string",
           "description": "Name of the SKU level."