Bump github.com/Azure/azure-sdk-for-go/sdk/azidentity from 1.5.2 to 1.6.0 in /get-started/azure-auth/go

Bump github.com/Azure/azure-sdk-for-go/sdk/azidentity from 1.5.2 to 1.6.0 in /get-started/azure-auth/go #236