Add Scenario set State method (#1322)

* Add SetScenarioState

* add tests

* summary

* .

* 1.8.13-preview-01

* fix

* fix name

src/WireMock.Net.Abstractions/Admin/Scenarios/ScenarioStateUpdateModel.cs

@@ -0,0 +1,15 @@
+// Copyright © WireMock.Net
+
+namespace WireMock.Admin.Scenarios;
+
+/// <summary>
+/// ScenarioStateModel
+/// </summary>
+[FluentBuilder.AutoGenerateBuilder]
+public class ScenarioStateUpdateModel
+{
+    /// <summary>
+    /// Gets or sets the NextState.
+    /// </summary>
+    public string? State { get; set; }
+}