Removed obsolete attributes

Author: ThomasArdal

src/Elmah.Io.NLog/ElmahIoTarget.cs

@@ -49,7 +49,6 @@ public class ElmahIoTarget : AsyncTaskTarget
         /// <summary>
         /// The API key from the elmah.io UI.
         /// </summary>
-        [RequiredParameter]
         public string ApiKey
         {
             get
@@ -68,7 +67,6 @@ public string ApiKey
         /// <summary>
         /// The id of the log to send messages to.
         /// </summary>
-        [RequiredParameter]
         public string LogId
         {
             get