inspired by temporalio/samples-go/mutex

1. Run a temporal service

   temporal server start-dev
2. In a different shell, run the example worker

   go run examples/mutex/main.go worker
3. In a different shell, execute the workflow

   go run examples/mutex/main.go sample-workflow-with-mutex --resource-id foo -d
   go run examples/mutex/main.go sample-workflow-with-mutex --resource-id foo -d