Merge pull request #44486 from bensack/patch-2

Update data-lake-storage-use-power-bi.md

Author: ktoliver

articles/storage/blobs/data-lake-storage-use-power-bi.md

@@ -22,6 +22,7 @@ Before you begin this tutorial, you must have the following:
 > * An Azure subscription. See [Get Azure free trial](https://azure.microsoft.com/pricing/free-trial/).
 > * A storage account that has a hierarchical namespace. Follow [these](data-lake-storage-quickstart-create-account.md) instructions to create one.
 > This article assumes that you've created an account named `myadlsg2`.
+> * You are granted one of the following roles for the storage account: **Blob Data Reader**, **Blob Data Contributor**, or **Blob Data Owner**.
 > * A sample data file named `Drivers.txt` located in your storage account.
 > You can download this sample from [Azure Data Lake Git Repository](https://github.com/Azure/usql/tree/master/Examples/Samples/Data/AmbulanceData/Drivers.txt), and then upload that file to your storage account.
 > * **Power BI Desktop**. You can download this from [Microsoft Download Center](https://www.microsoft.com/download/details.aspx?id=45331).