Added TempFile activity

src/activities/Elsa.Activities.File/Activities/TempFile/TempFile.cs

@@ -0,0 +1,21 @@
+using Elsa.ActivityResults;
+using Elsa.Attributes;
+using Elsa.Services;
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Text;
+
+namespace Elsa.Activities.File
+{
+    [Action(Category = "File",
+        Description = "Created a temporary file and returns its path",
+        Outcomes = new[] { OutcomeNames.Done })]
+    public class TempFile : Activity
+    {
+        protected override IActivityExecutionResult OnExecute()
+        {
+            return Done(Path.GetTempFileName());
+        }
+    }
+}

src/activities/Elsa.Activities.File/Activities/TempFile/TempFileBuilderExtensions.cs

@@ -0,0 +1,13 @@
+using Elsa.Builders;
+using System;
+using System.Collections.Generic;
+using System.Runtime.CompilerServices;
+using System.Text;
+
+namespace Elsa.Activities.File
+{
+    public static class TempFileBuilderExtensions
+    {
+        public static IActivityBuilder TempFile(this IBuilder builder, [CallerLineNumber] int lineNumber = default, [CallerFilePath] string? sourceFile = default) => builder.Then<TempFile>(null, lineNumber, sourceFile);
+    }
+}