Bump github.com/Azure/azure-sdk-for-go/sdk/azidentity from 1.3.1 to 1.4.0 in /get-started/azure-auth/go

Bump github.com/Azure/azure-sdk-for-go/sdk/azidentity from 1.3.1 to 1.4.0 in /get-started/azure-auth/go #90