Add two new sku names for StorageAccount (#5547)

Author: huizlAzure

specification/storage/resource-manager/Microsoft.Storage/stable/2019-04-01/storage.json

@@ -1019,7 +1019,9 @@
             "Standard_RAGRS",
             "Standard_ZRS",
             "Premium_LRS",
-            "Premium_ZRS"
+            "Premium_ZRS",
+            "Standard_GZRS",
+            "Standard_RAGZRS"
           ],
           "x-ms-enum": {
             "name": "SkuName",