Update IoT Hub control plane to new version (2021-03-31)

eng/mgmt/mgmtmetadata/iothub_resource-manager.txt

@@ -3,12 +3,12 @@ AutoRest installed successfully.
 Commencing code generation
 Generating CSharp code
 Executing AutoRest command
-cmd.exe /c autorest.cmd https://github.com/Azure/azure-rest-api-specs/blob/master/specification/iothub/resource-manager/readme.md --csharp --version=v2 --reflect-api-versions --tag=package-2020-03 --csharp-sdks-folder=C:\code\Azure\asfn1\sdk
-2021-05-05 18:24:00 UTC
+cmd.exe /c autorest.cmd https://github.com/Azure/azure-rest-api-specs/blob/master/specification/iothub/resource-manager/readme.md --csharp --version=v2 --reflect-api-versions --csharp-sdks-folder=C:\code\Azure\asfn1\sdk
+2021-05-13 18:36:24 UTC
 Azure-rest-api-specs repository information
 GitHub fork: Azure
 Branch:      master
-Commit:      a394eccc2ce26369cacbc113cf0c3a9c9501e689
+Commit:      7d4caa5e1c9996a25300b0b23ef426667e4a7bde
 AutoRest information
 Requested version: v2
 Bootstrapper version:    autorest@2.0.4413

sdk/iothub/Microsoft.Azure.Management.IotHub/AzSdk.RP.props

@@ -1,7 +1,7 @@
 <Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
   <!--This file and it's contents are updated at build time moving or editing might result in build failure. Take due deligence while editing this file-->
   <PropertyGroup>
-    <AzureApiTag>Devices_2020-03-01</AzureApiTag>
+    <AzureApiTag>Devices_2021-03-31</AzureApiTag>
     <PackageTags>$(PackageTags);$(CommonTags);$(AzureApiTag);</PackageTags>
   </PropertyGroup>
 </Project>