add Alignment for ButtonTemplateMessage

src/Infrastructure/BotSharp.Abstraction/Messaging/Enums/AlignmentEnum.cs

@@ -0,0 +1,20 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace BotSharp.Abstraction.Messaging.Enums
+{
+    public static class  AlignmentEnum
+    {
+        public const string TopLeft = "topLeft";
+        public const string BottomLeft = "bottomLeft";
+
+        public const string TopRight = "topRight";        
+        public const string BottomRight = "bottomRight";
+
+        public const string TopCenter = "topCenter";
+        public const string BottomCenter = "bottomCenter";
+    }
+}

src/Infrastructure/BotSharp.Abstraction/Messaging/Models/RichContent/Template/ButtonTemplateMessage.cs

@@ -20,4 +20,7 @@ public class ButtonTemplateMessage : IRichMessage, ITemplateMessage
 
     [JsonPropertyName("is_horizontal")]
     public bool IsHorizontal { get; set; }
+
+    [JsonPropertyName("alignment")]
+    public string Alignment { get; set; } = AlignmentEnum.TopLeft;
 }