Merge pull request #24 from teghoz/feature/Transaction_ID_Type_Update

Change transaction id from i32 to i64
This is in accordance with PayStack's updates.

src/main/Apis/Transactions/List.cs

@@ -102,7 +102,7 @@ public class Customer
         public class Datum
         {
             [JsonProperty("id")]
-            public int Id { get; set; }
+            public long Id { get; set; }
 
             [JsonProperty("domain")]
             public string Domain { get; set; }