fix(sample): Fix WebApiSample InvalidCastException when casting JObject to string

Author: hieuxlu

src/samples/WebApiSample/WebApiSample/Workflows/TestWorkflow.cs

@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.Linq;
 using System.Threading.Tasks;
+using Newtonsoft.Json.Linq;
 using WorkflowCore.Interface;
 using WorkflowCore.Models;
 
@@ -18,7 +19,15 @@ public void Build(IWorkflowBuilder<MyDataClass> builder)
             builder
                 .StartWith(context => ExecutionResult.Next())
                 .WaitFor("MyEvent", (data, context) => context.Workflow.Id, data => DateTime.Now)
-                    .Output(data => data.Value1, step => step.EventData)
+                .Output((data, step) =>
+                {
+                    var jsonData = data.EventData as JObject;
+                    if (jsonData != null)
+                    {
+                        var value = jsonData.ToObject<MyDataClass>();
+                        step.Value1 = value?.Value1;
+                    }
+                })
                 .Then(context => Console.WriteLine("workflow complete"));
         }
     }