Add NewDeleteMessage

Signed-off-by: Jianqiu Zhang <zhangjianqiu13@gmail.com>

helpers.go

@@ -19,6 +19,13 @@ func NewMessage(chatID int64, text string) MessageConfig {
 	}
 }
 
+func NewDeleteMessage(chatID int64, messageID int) DeleteMessageConfig {
+	return DeleteMessageConfig{
+		ChatID:    chatID,
+		MessageID: messageID,
+	}
+}
+
 // NewMessageToChannel creates a new Message that is sent to a channel
 // by username.
 //