Adds broadcast toogle to chat.postmessage

Author: johnkors

source/src/Slackbot.Net.SlackClients.Http/Models/Requests/ChatPostMessage/ChatPostMessageRequest.cs

@@ -17,6 +17,7 @@ public class ChatPostMessageRequest
     public Attachment[] attachments { get; set; }
 
     public IBlock[] Blocks { get; set; }
+    public bool? Reply_Broadcast { get; set; }
 }
 
 public class Attachment

source/test/Slackbot.Net.SlackClients.Http.Tests/ChatPostMessageTests.cs

@@ -32,6 +32,20 @@ public async Task PostWorks()
         var response = await SlackClient.ChatPostMessage(msg);
         Assert.True(response.Ok);
     }
+    
+    [Fact]
+    public async Task PostWithBroadCastWorks()
+    {
+        var msg = new ChatPostMessageRequest
+        {
+            Channel = "CTECR3J6M",
+            thread_ts = "1679186947.684479",
+            Text = "BROADCAST!",
+            Reply_Broadcast = true
+        };
+        var response = await SlackClient.ChatPostMessage(msg);
+        Assert.True(response.Ok);
+    }
 
     [Theory]
     [InlineData(true)]