fix for messagebird#110 ContentType is missing 'whatsAppSticker' and …

…throws

MessageBird/Objects/Conversations/Content.cs

@@ -13,6 +13,7 @@ public enum ContentType
         [EnumMember(Value = "text")] Text,
         [EnumMember(Value = "video")] Video,
         [EnumMember(Value = "event")] Event,
+        [EnumMember(Value = "whatsappSticker")] WhatsAppSticker,
     }
 
     public class Content
@@ -37,5 +38,8 @@ public class Content
 
         [JsonProperty("video")]
         public MediaContent Video {get;set;}
+
+        [JsonProperty("whatsappSticker")]
+        public WhatsAppStickerContent WhatsAppSticker { get; set; }
     }
 }

MessageBird/Objects/Conversations/WhatsAppStickerContent.cs

@@ -0,0 +1,14 @@
+using Newtonsoft.Json;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace MessageBird.Objects.Conversations
+{
+    public class WhatsAppStickerContent
+    {
+        [JsonProperty("link")]
+        public string Link { get; set; }
+    }
+}