SDK Go Update Quickstart to use DaprWorkflowClient

[elena-kolevska]

#1118

[elena-kolevska]

Already uses the workflow client

[jake-engelberg]

/assign

[jake-engelberg]

I don't see any usage of the deprecated workflow methods...:
(StartWorkflowBeta1(), GetWorkflowBeta1(), ResumeWorkflowBeta1(), etc)
...from github.com/dapr/go-sdk/client in the go workflow quickstart.
The client package is only being used for state store in the quickstart.
workflows/go/sdk/order-processor/main.go:139

Instead, I already see usage of the new github.com/dapr/go-sdk/workflow methods:
(ScheduleNewWorkflow(), FetchWorkflowMetadata(), RaiseEvent(), etc)
workflows/go/sdk/order-processor/main.go:84