update user agent version

Author: mediumTaj

src/IBM.WatsonDeveloperCloud/Constants.cs

@@ -26,7 +26,7 @@ public class Constants
         /// The version number for this SDK build. Added to the header in 
         /// each request as `User-Agent`.
         /// </summary>
-        public const string SDK_VERSION = "watson-apis-dotnet-sdk/2.2.2";
+        public const string SDK_VERSION = "watson-apis-dotnet-sdk/2.3.0";
         /// <summary>
         /// A constant used to access custom request headers in the dynamic
         /// customData object.