Update AutoRest C# version (#21569)
Update AutoRest C# version (#21569)

Update AutoRest C# version to 3.0.0-beta.20210603.1
AsrOneSdk/azure-sdk-for-net,AsrOneSdk/azure-sdk-for-net,AsrOneSdk/azure-sdk-for-net,AsrOneSdk/azure-sdk-for-net